[HN Gopher] Blood test that finds 50 types of cancer is accurate...
___________________________________________________________________
Blood test that finds 50 types of cancer is accurate enough to be
rolled out
Author : kieranmaine
Score : 528 points
Date : 2021-06-25 09:35 UTC (13 hours ago)
(HTM) web link (www.theguardian.com)
(TXT) w3m dump (www.theguardian.com)
| londons_explore wrote:
| More technologies like this are coming...
|
| Is it worth taking blood samples now, keeping them in a freezer,
| and then waiting for the test tech to come so I can get it tested
| to see disease progression of whatever disease I get when I get
| older?
| cfontes wrote:
| why would it matter desides for informational purposes?
| dmichulke wrote:
| In an extreme case you could prove that you had your "it
| kills you within the year" cancer already a few years ago.
| plank_time wrote:
| That's what scientific studies will produce. They won't
| need your particular blood for that. You as an individual
| only care if you have cancer at the time of the blood test.
| elif wrote:
| I take blood tests regularly. They are very picky about sample
| collection time.
| cromka wrote:
| Same thing with stool collection.
| mritchie712 wrote:
| yes, having mysterious blood in your freezer is a good
| conversation starter for guests too. Bonus points if you get
| creative with the labels for each sample.
| criddell wrote:
| If one wanted to invest in the people doing this kind of work,
| what would you buy? Grail isn't public and I'm not a venture
| capitalist.
| gww wrote:
| There are multiple academic startup companies now trying to do
| cfDNA tests. They have all acquired patents from a paper or
| two. I would be wary about many of the early stage ones as they
| are not truly proven or have demonstrated scale.
| cinntaile wrote:
| Illumina has made an offer to buy back Grail but several
| antitrust cases have halted the process for now.
| dharma1 wrote:
| This is great progress. Can you get this done privately in the
| UK? I see only for 50+ on the NHS
| doctoring wrote:
| Highly encourage reading the paper referred to (but not linked!)
| in the article:
|
| https://www.annalsofoncology.org/article/S0923-7534(21)02046...
|
| Some good breakdown of test performance by stage and cancer
| types.
| invisible wrote:
| There is a big discussion in this post about iatrogenics being
| introduced by these tests. It sounds like the fear here is that
| it'll tax an already burdened system with more patients (some of
| which just got a false positive).
|
| I'm failing to understand how that's any different from other
| blood tests: they signal a problem, then more has to be
| established to validate the signal. Nobody is saying "this test
| proves someone has cancer" and I'm pretty sure doctors already
| have to discuss how tests can be inaccurate with patients. I
| believe it's the case that symptoms of cancer (just like other
| illnesses) may be ignored exactly because there aren't any other
| signals to indicate cancer. Plus zebras and horses and all of
| that too. Perhaps someone does have symptoms but nobody connects
| the dots, and these tests might connect those dots? Is there some
| reason that this argument is invalid in medical science?
| cma wrote:
| Chalk it up to the techno-rationalist community saying doctors
| can't handle bayesian statistics, on the basis of results of
| brain teaser surveys, and then extending that to anything
| related to testing or medicine.
| robomartin wrote:
| Interesting.
|
| My mom passed away two days ago. She was diagnosed with
| pancreatic cancer, stage 4, at the start of the pandemic.
| Needless to say, it was a rough fifteen months.
|
| What would the outcome and options have been with a diagnosis a
| year or more earlier? My guess is this could have saved her life.
|
| As for the question of whether or not knowing is beneficial or
| not, I agree with commenters who said this could have serious
| negative consequences.
|
| Neither her or my father, who is 93, knew what she had. It would
| have been horribly difficult for her to handle given her
| personality. He would have been devastated.
|
| In this case I am speaking of stage 4. There is no stage 5.
|
| My guess is the psychological impact of learning of "stage 0.1"
| cancer, along with a treatment plan to eradicate it would have
| been easy to handle for both of them.
|
| That's the key I think. Most people are wired to handle a problem
| if there is a solution. Nobody worries about a broken leg or most
| cuts these days because we know we can treat them.
|
| Please no condolences responses. I know everyone reading this
| will feel compelled to offer them. I appreciate the gesture. That
| could very well take over this thread and that is not my intent.
| A good discussion of the subject is enough for me. Thanks.
| [deleted]
| Engineering-MD wrote:
| For those interested in reading the actual paper, this appears to
| be it (open access too):
|
| https://www.annalsofoncology.org/article/S0923-7534(21)02046...
|
| I've only skimmed it, but seen quite a few limitations, notably
| those with "non-malignant conditions at enrolment" (it would be
| nice to know more what that means), previous cancer or recent
| corticosteroids use were excluded. Additionally, it's a case
| controlled trial which don't always translate to screening tools
| (as mentioned in their own discussion).
|
| The problem with screening is that you are doing something on
| healthy patients, so particularly for rare cancers even a small
| risk of a false positive is significant. In this case it's 99.5%.
| So if you test 1,000,000 people, 5000 (*correction from 500)
| people will come up positive. This is great for common diseases,
| but if it's rare and only 1 in a million has it then you have got
| 5000 false positive for every 1 positive.
|
| I think this will likely be a useful test (if it translates well
| to a wider screening population), but it's not as good as it
| first seems.
| vharuck wrote:
| >"non-malignant conditions at enrolment" (it would be nice to
| know more what that means)
|
| My guess is they're referring to the neoplasm behavior codes
| defined by the WHO in the International Classification of
| Diseases for Oncology (see article's references for info).
| Which means "malignant" is a neoplasm which has begun spreading
| beyond the tissue it appeared in. Non-malignant neoplasms are
| either benign (not likely to ever spread), borderline (could go
| either way), or _in situ_ (still in the original tissue, but it
| will spread).
|
| North American cancer registries typically don't even bother
| collecting records of benign or borderline tumors. The only
| exceptions are brain tumors, which can be deadly without
| metastasizing. Registries also don't collect cervical cancer
| _in situ_ records because there are so many and a lot of
| physicians never bothered reporting them. And finally,
| oncologists and epidemiologists classify urinary bladder cancer
| in situ as malignant because it 's really hard for physicians
| to differentiate. Better safe than sorry, in case.
| robocat wrote:
| > 500 people
|
| 5000 people
| Engineering-MD wrote:
| Yes thank you missed a zero
| myle wrote:
| Cancer is not that rare. It ia one of the most common causes of
| death. I believe second to heart attacks.
| dmitryminkovsky wrote:
| One of my great fears in life is that employers/insurers will
| impose this en masse on people, causing immeasurable harm to the
| mental health of people who can't handle the anxiety that this
| type of approach to medicine would cause. I'm definitely a big
| proponent of evidence-based medicine and using it to help living
| quality life as long as possible, but this sort of thing would
| just wreck my day to day existence and destroy my quality of
| life. I am not a server in a data center. I am a human with
| consciousness and emotions, the desire to live, and a fear of
| suffering and death.
| hans1729 wrote:
| One of your greatest fears in life is to be regularly checked
| for diseases that would end your life unless thy are detected
| in time?
|
| ...What?
|
| e: you mean the emotional distress caused by the process? But
| that's just in your head, and it's beyond irrational. Getting
| checked is _inherently a good thing_. Even if you are extremely
| anxious, the people who love you want you to live - this is a
| psychological problem that you should work through, not one
| with the testing
| TaupeRanger wrote:
| No, you are flat out wrong and anyone with an understanding
| of good health policy will understand this. Screening can
| lead to iatrogenics and unnecessary costs. It is not
| automatically a net gain, it has to PROVE that it makes
| patients live longer or better, just like any other
| intervention. And in many cases, screening policies actually
| make things worse for all kinds of reasons.
| dmitryminkovsky wrote:
| Yes that is right. I make no claims to being a rational
| being. I am at best pseudo rational. As much as I love
| computers, I make no claim to being one. I am a human.
|
| And yes, I do also greatly appreciate evidence based
| medicine. There are many terminal illnesses where there is no
| evidence that constant screening improves outcomes. My
| impression is that people successfully market products like
| this to give people a false sense of control tire through
| micromanagement where given the state of the art, control is
| lacking.
| asdfasgasdgasdg wrote:
| > My impression is that people successfully market products
| like this to give people a sense of control where given the
| state of the art, control is lacking.
|
| There can be no such evidence for a screening method like
| this, because it is brand new. We may find that even
| detection as early as Grail provides is still insufficient,
| but we don't and can't know yet. Certainly with many
| cancers earlier detection does lead to better outcomes. You
| also seem to be focusing on cases where screening has not
| improved outcomes while ignoring cases where it has.
| hans1729 wrote:
| That still escapes the main argument: your problem isn't
| the medicine, your problem is your anxiety.
|
| If "this sort of thing would just wreck your day to day
| existence and destroy your quality of life" (let your own
| wording sink in), you should work through that exact
| problem, probably rather sooner than later.
|
| Detecting diseases before they _actually destroy your life_
| isn 't bad, it's good - and so you should perceive it as
| good. Not because you're a rational acteur, but because
| it's literally, by definition, in your personal best
| interest. Take a step back from the panic, just purely
| observe, and try to see it for what it is: it prevents real
| suffering - your own _very real_ suffering - and the price
| to pay is working through _imaginary_ suffering.
|
| Getting your blood checked isn't linearly related with
| fears of death, the exact opposite is the case. Try to see
| it for what it actually is, instead of intuitively letting
| panic-mode take over. If your intuition doesn't serve your
| well-being, proactively go ahead and fix your intuition -
| you can.
| andai wrote:
| Do you mean the psychological impact of the screenings,
| constantly wondering if you have cancer, if the test missed
| anything etc, rather than fear of the procedure itself?
| nevinera wrote:
| 0.5% false positive rate is actually _quite_ high. I don 't have
| the numbers, but I'd be surprised if more than 1% of the people
| that would receive such a screening _actually already have
| cancer_ , which would mean that it produces about as many false
| positives as false negatives.
|
| Picture a population of a million people, all receiving the test.
| 1% of them _have_ cancer (unknown to them) - half of _those_
| people get a negative screening result and half get a positive
| one (51% successful identification), and 0.5% of the _full
| population_ get a negative screening result. Those numbers are
| roughly equal.
|
| That doesn't make it useless by any means, but it's not nearly as
| 'specific' as it sounds on paper.
| vmception wrote:
| So still get a second opinion just as you would have anyway.
|
| It's still getting caught
| gradys wrote:
| There's an interesting discussion raging on elsewhere in the
| thread about the possibility for cultural adaptation that would
| enable us to cope with statements like "the cancer test was
| positive, but there's still a decent chance you don't have
| cancer".
|
| There's also an interesting question, taking your roughly 1:1
| true to false positive ratio as an example, of whether the
| marginal true positive does more good for the world than the
| marginal false positive.
|
| Side-stepping those questions though, they probably won't give
| this test to literally every person in the population. How much
| does the picture improve when you give this only to people over
| 50? Or only smokers? You could still massively increase
| effective screening for cancer with a cheap and easy test if
| you combine it with enough population filtering to increase the
| true positive/false positive ratio to something like 70-90%
| rather than the 50%
| nevinera wrote:
| That side-step was my actual assumption - I can't imagine
| that 1% of the _whole population_ currently has actionable
| cancer.
|
| But yes, the higher you drive the prior, the less the false-
| positives cost. That's a fairly normal situation - it's why
| they have to evaluate the cost-value of further-investigation
| against so many different population groups to determine the
| actual optimal usage.
|
| And yes, the question I was trying to prompt really is "what
| information would we need to have in order to know when this
| test is a net positive, from the patient's perspective" (and
| separately, "from the insurance company's perspective", since
| that's likely to have a very different answer).
| moralestapia wrote:
| I feel it's a net win anyway, if the procedure is not invasive
| and cheap, you could take one every so often (yearly?) and if
| something shows up you just double check with a better method
| or w/e. Better than nothing, which is the current alternative.
| colinmhayes wrote:
| The problem is people are idiots. They get a false positive
| and their doctors tells them "well there are a lot of false
| positives with this test" but all people hear is "you have
| cancer." Then they get an invasive biopsy because the
| healthcare system is glad to take your money.
| scarecrowboat wrote:
| What if the followup procedure is invasive and expensive?
| It's possible that this procedure could be net negative in
| aggregate depending on the % of false positives and # of
| resulting needless followup procedures. Not to mention the
| emotional stress.
| timy2shoes wrote:
| Exactly! This reminds of the recent case of the AMA
| increasing the suggested age of regular mammograms. More
| testing means earlier detection of breast cancer. But a
| false positive means an invasive biopsy. These are the two
| sides that need to be balanced. The AMA decided that since
| the base rate of cancer is so low in women under 50, the
| posterior probability that you have cancer given a positive
| mammogram for the under 50 age group is considerably low.
| Therefore they decided that the increased costs (monetary
| and emotional) do not outweigh the benefits.
|
| From https://www.ama-assn.org/sites/ama-
| assn.org/files/corp/media...
|
| "Screening mammography reduces mortality from breast
| cancer, including in women younger than age 50 years.
| However, screening mammography carries harms such as false
| positive results that can lead to additional imaging and
| invasive biopsy procedures, and overdiagnosis that could
| lead to treatment in patients who may not benefit from it.
| The USPSTF considered the balance of benefits and harms
| using a commissioned targeted systematic evidence review of
| randomized clinical trials and a decision analysis that
| compared the expected health outcomes of starting and
| ending mammography at different ages and using annual and
| biennial screening strategies; it concluded (in part) that
| routine screening should begin at age 50 years and continue
| biennially until age 74 years."
| moralestapia wrote:
| >But a false positive means an invasive biopsy.
|
| Nah, there's plenty of other things you'd try before the
| biopsy.
| moralestapia wrote:
| Don't do it, then. Try homeopathy or whatever thing feels
| good for you.
| Robotbeat wrote:
| Right. If the objection is that it has a high false positive
| rate and doctors don't understand Bayesian statistics enough
| to take that into account, then the solution isn't to ban the
| test but instead require clinicians who interpret the test to
| learn Bayesian statistics better.
| randcraw wrote:
| I would very much like to know the confusion matrix for all
| these component tests: the false positive rate, false negative
| rate, i.e., the sensitivity and specificity of each.
|
| For example, the Prostate Specific Antigen (PSA) test is famous
| for a high false positive rate, inviting many men to worry
| needlessly or get unwarranted biopsies. The current state of
| any test and its history are important to know for both patient
| and doctor, so both can have an informed dialog about the
| options after a positive result.
|
| Also, each of these 50 tests are going to evolve over time, as
| will the accuracy of error rates for patient subpopulations.
| Race, age, ethnicity, co-morbidities and co-maladies will each
| shift the accuracy and precision of each test in ways that will
| make them much more useful if everyone stays well informed
| about _all_ their merits and demerits.
| Zenst wrote:
| Whole area of having tests that give definitive answers in the
| field of health is the one area in which it can't get enough of.
| Biggest issue health wise many have is time from issue to getting
| a correct diagnoses, whatever the ailment.
| TaupeRanger wrote:
| No, not according to the statistics. You are orders of
| magnitude more likely to be harmed from unnecessary
| diagnosis/treatment (including cost and psychological damage)
| than to be undiagnosed and have a worse outcome as a result. We
| find most things that we are capable of finding.
| hunter-2 wrote:
| I hope this test becomes mainstream in the next few years. One of
| those things that the world desperately needs.
|
| There is another company in India, Tzar Labs, that has been
| working on a similar test and is almost ready to launch as well.
|
| https://epaper.livemint.com/Home/ShareArticle?OrgId=75ef980c...
| sbelskie wrote:
| > The test, which is also being piloted by NHS England in the
| autumn, is aimed at people at higher risk of the disease
| including patients aged 50 or older.
|
| Does anyone know if the study was performed with a population
| that matches this description? Curious if the rates are in a
| general population or this higher risk group.
| plank_time wrote:
| Why wait until 2023 for a larger study? This is a game changing
| technology that should be pursued like the COVID vaccine. We
| should be dumping billions into this across the globe to improve
| its accuracy and drive costs down.
| konschubert wrote:
| If you're tested positive, what's the probably that you actually
| have cancer?
|
| (The article states 0.5% false positive rate and about 50% true
| positive rate, but I would need to know the the prevalence of
| cancer in the population to compute what I am asking for).
| sxyuan wrote:
| The paper discusses this:
| https://www.annalsofoncology.org/article/S0923-7534(21)02046...
|
| I believe the name for what you describe is "positive
| predictive value" or PPV - defined in the paper as the
| "proportion of true positives among those with a positive test
| result". According to the paper, their PPV for cancer detection
| is 44.4% (28.6%-79.9%, presumably the 95% CI).
|
| As a point of comparison, one source I found reports a much
| lower PPV for the mammogram - single digits on initial
| screening, rising to 28% post biopsy: https://www.bcsc-
| research.org/statistics/screening-performan...
|
| The paper notes that PPV can be a more useful metric than
| sensitivity. Their multi-cancer approach includes some hard to
| detect cancers that decrease the overall sensitivity, but
| increase PPV.
|
| Edit: the paper also states: "The extrapolated PPV reported
| here based on SEER cancer incidence and clinical stage
| distribution was 44.4% in the screening-eligible 50-79-year age
| group, which is higher than that of currently recommended
| screening tests, as PPV is driven by specificity and population
| incidence."
|
| They also add the caveat that "studies in intended-use
| populations that will provide more accurate PPV estimates are
| ongoing".
| thebelal wrote:
| One of the cancers they mention is pancreatic cancer.
|
| A quick Google search suggests the prevalence of pancreatic
| cancer in the population is 13 per 100,000.
|
| So if you gave this test with a 0.005 false positive rate and
| 0.5 true positive rate to 100,000 people it would miss diagnose
| 500 people and only correctly detect 7 cancers.
|
| So given you had a positive test result there would be a
| 1-(7/500)=98.6% chance you did _not_ have pancreatic cancer.
|
| Doesn't seem very useful in that light...
| kieranmaine wrote:
| Does this take into account age?
|
| The article says:
|
| "The test, which is also being piloted by NHS England in the
| autumn, is aimed at people at higher risk of the disease
| including patients aged 50 or older"
| whiterock wrote:
| The test is aimed at people over 50 were, sadly, the
| prevalence is much higher!
| konschubert wrote:
| The false positive rate of 0.5% refers to the chance that
| there is ANY false positive in the whole screening, not just
| a false positive on the pancreatic cancer segment.
| kieranmaine wrote:
| It seems like there are a number of other risk factors as
| well (see https://www.cancerresearchuk.org/health-
| professional/cancer-...), that could shrink the pool of
| people tested.
| konschubert wrote:
| Let's say 1% of ppl have cancer at any given moment -
|
| So if we test a random person, there is a 1% * 50% = 0.5%
| chance that person is tested positive for cancer because they
| have cancer.
|
| And a 0.99% * 0.5% = 0.5% chance that a person is tested false
| positive.
|
| This means if the test shows positive for somebody, it's about
| 50-50 that they actually have cancer - correct?
| konschubert wrote:
| This is actually pretty good and could reasonably be used for
| screening in higher-risk populations.
| tyrex2017 wrote:
| Correct.
|
| Thats why it may be a good idea to test higher risk
| populations or people with health issues.
|
| It could make the ratio of absolute true positives to false
| positives 10x better
| epmaybe wrote:
| I don't have much to add to the discussion here. Sensitivity is
| poor, specificity is pretty good and could be better if used as a
| confirmatory test(?). What I found interesting in the comments is
| how many people involved in healthcare lurk on a forum very much
| not dedicated to healthcare. Kind of cool. You all should chime
| in more, I learned a lot.
| rackjack wrote:
| So many tech people here thinking they know how the entire
| medical industry works... medical problems and the research that
| arises from them are staggeringly complex and messy. Please... if
| you've never had experience with this kind of thing, don't
| pretend that you do. Some uninformed person might see your
| comment and think you actually know something.
| DoubleDerper wrote:
| Shortcut to the source of the technology...
|
| https://grail.com/
| starkd wrote:
| "It correctly identified when cancer was present in 51.5% of
| cases, across all stages of the disease, and wrongly detected
| cancer in only 0.5% of cases."
|
| Doesn't this seem kind of low? Just a bit better than a coin
| flip. Of course, it rises to 65% and 87% for certain
| circumstances and the false positive rate is low, but it seems
| like a lot of cancers could fail to be detected and give a false
| assurance patients are cancer free. When symptoms emerge later
| they may be less concerned with getting it checked out. Is this
| in line with standard performance of tests?
| phunehehe0 wrote:
| This is much better than a coin flip. A coin flip would give
| about 50% true positive rate (which is about the same as the
| test), but it would also give about 50% false positive rate.
|
| To put it in perspective, imagine 10 people have cancer in a
| population of 1000 (a rate of 10% which is too high compared to
| what I think the real number should be). The test would fail to
| identify 5 of the people with cancer, and it would say that 5
| of the people without cancer have cancer. So overall it would
| misidentify 10 people. The coin flip would misidentify 500
| people.
|
| Amusingly in this example if you have a "test" that just says
| nobody has cancer it would also misidentify only 10 people :) I
| think this is why they are reporting true positive rate and
| false positive rate.
| starkd wrote:
| I see. I guess its more important to keep false positives low
| than increase detection accuracy.
|
| Thank you very much for this explanation.
| noway421 wrote:
| Elizabeth Holmes would be proud
| cronix wrote:
| One day you'll put your finger on a sensor on your phone that
| pricks you to get a drop of blood and analyze it right there on
| the spot. Kinda like square does for mobile credit card payments.
|
| Maybe that's how you'll unlock it too, which might help with
| phone addiction /s
| victor106 wrote:
| > It correctly identified when cancer was present in 51.5% of
| cases, across all stages of the disease, and wrongly detected
| cancer in only 0.5% of cases.
|
| While I think this is a great step forward, How can this be
| described as highly accurate when it missed identifying cancer in
| 48.5% of the people?
| doctoring wrote:
| Cancer radiologist here!
|
| I don't know about "highly accurate", but certainly pretty
| fucking good. Because for most of those cancers for most
| populations, the asymptomatic detection rate is much, much
| lower. Like close to 0%.
|
| There is no general population screening test for, say,
| pancreatic cancer or ovarian cancer etc.
| jacquesm wrote:
| And is only 18% accurate when looking at stage 1 cancers.
|
| https://www.theguardian.com/science/2020/mar/31/new-blood-te...
| reacharavindh wrote:
| This is one of those medical revolutions that I am waiting dearly
| for.
|
| Facilities that are not hospitals(to avoid the risk of occupying
| medical devices that sick people need) built to _regulary_ check
| up otherwise healthy people for preventive care.
|
| Heck, I have so many alerts defined on my monitoring setup for
| servers to watch for signals of failure before they get too big.
| But, my own body is not observed until something bad needs
| treatment. Why can't we observe ourselves medically and analyze
| that record for early signs of trouble before it becomes
| serious?!
|
| All the advancement in technology in recent years, this ought to
| happen sooner than later.
| dukeofdoom wrote:
| One issue is that your body may have all types of tissues that
| might be precancerous or slow growing cancerous growths that
| the test will identify. To get to them and remove them would do
| far more damage than leaving them alone. Even with things like
| prostate cancer, which is fairly easy to get to. Leaving it
| alone, is often the right choice depending on the age of the
| patient and speed of growth of the cancer.
| DoreenMichele wrote:
| _Why can't we observe ourselves medically and analyze that
| record for early signs of trouble before it becomes serious?!_
|
| We can and plenty of people do, usually with tools like health
| journals and smart watches recording biometrics.
| sbelskie wrote:
| A big part of this is the fact that learning information (about
| a disease or condition) early is often NOT the same thing as
| learning information that will change a patient's clinical
| outcome.
| radu_floricica wrote:
| I never understood this. I mean I totally get the concept,
| but I don't get how it came to influence policy. Put it like
| this: how many people are you willing to kill to make sure
| people don't find out they're sick? Because that's what it
| boils down to. And it sounds... sociopathic.
| colinmhayes wrote:
| How many people are you willing to give chemo to even
| thought they don't have cancer to save a life? Over zealous
| testing makes outcomes worse.
| vidarh wrote:
| How many people are you willing to kill with too excessive
| testing programs? Because that is part of the equation too.
| It's easy to ignore because chances of harm from non-
| invasive-ish testing like a blood test is low.
|
| The problem is that it compounds quickly.
|
| Consider:
|
| * For a rare condition you need a _lot_ of tests to find
| them. Let 's say you look for something that 1 in a million
| can be expected to have.
|
| * When you find those 1 in a million, the testing needs to
| save them, which means a proportion of them need to
| otherwise be significantly affected. Let's say 1 in 10 of
| them die.
|
| * When you find those 1 in 10 million that has the
| condition that would have died without intervention, early
| intervention needs to actually make a difference. Let's say
| 1 in 10 of those actually survive because of early
| detection.
|
| Now you have to do ~100 million tests to save one life.
|
| Suddenly 100 million:1 odds of dying as a result of a visit
| to do a blood test are enough to neutralise the benefit, be
| it infections or accidents etc.. And that includes
| secondary effects such as delayed diagnosis because a false
| negative leads a patient to delay seeking a second opinion
| once symptoms present.
|
| Additionally there's the opportunity costs in terms of
| saving lives by spending the money elsewhere, such as e.g.
| awareness of symptoms and the like, or addressing entirely
| different issues.
|
| Of course, if you have a more common condition, and/or a
| condition that is much more lethal, and/or a condition
| where early intervention makes a difference, this all
| changes.
|
| But it's worth noting how little mass screening we do - as
| it turns out, it's hard to find conditions where the
| benefits are substantial enough to be worthwhile. In some
| cases, such as the use of mass screening for breast cancer,
| there has been calls to scale it back some places because
| it was unclear whether there was a net benefit.
| radu_floricica wrote:
| You're missing a step. There are several responses saying
| basically the same thing (testing kills), and more or
| less randomly I'm going to answer yours. All have the
| same step missing.
|
| Testing doesn't kills by itself, not in numbers worth
| mentioning. Treatments - sure, a whole different ball
| game, they're positively dangerous. But between testing
| and treatments there should be a specialist that crunches
| the numbers and comes to a decision. Which, like in the
| mammogram example above, is not always going to be more
| aggressive testing.
|
| What testing does is give you more information, which in
| a remotely sane system should lead to better decision
| making. Of course, I can imagine insane systems where,
| for example, the patient decides, the insurance pays and
| the doctor can be sued for discouraging treatments. In
| this particular combo you probably want to avoid doing
| mammograms to 20 yo, because the chance of a false
| positive is 1%, the chance of a true positive is 0.01%,
| and you end up with perverse chains leading to healthy
| people doing chemo. Like I said in the original comment,
| I GET the phenomenon. What I don't get however is how it
| can get even close to conventional wisdom that you want
| to avoid testing, as a rule. That's a particular fix to a
| particularly insane incentive combo, and common sense
| should make everybody rail against the insane incentive
| combo, and not act like the niche fix is actually a goal.
|
| I can't really explain how this came to be. Maybe people
| stumbled on an explanation of how extra testing _may_ be
| harmful, and the idea was so cool that it got stripped of
| context and became a meme in itself.
| vidarh wrote:
| > Testing doesn't kills by itself, not in numbers worth
| mentioning.
|
| Mammography involves radiation and pressure. The
| radiation alone is a significant risk [1], and kills by
| _causing cancer_. It can also cause tumors to rupture and
| spread malignant cells. It 's significant enough to
| significantly increase the hurdle where mammography is
| justified. It does not mean it never is - absolutely not.
| But it means screening programs need to be targeted.
|
| > What I don't get however is how it can get even close
| to conventional wisdom that you want to avoid testing, as
| a rule.
|
| It's not conventional wisdom that you want to avoid
| testing. That is for example what led to a lot of really
| aggressive campaigns for extensive breast cancer
| screening.
|
| What we saw was a small improvement in outcomes on a
| small number of positive test results, for a level of
| testing that suggested it was necessary to take into
| account other factors.
|
| Breast cancer screening was rolled back many places, or
| widening of the age bracket was halted as a result of
| looking at outcomes and realising that "conventional
| wisdom", which used to be that _more testing was
| inherently good_ was flawed.
|
| There are clear, quantifiable harms from it, ranging from
| actual risks of _causing cancer_ or _causing spread of
| cancer_ with mammography. These risks are low enough to
| be worth it for certain patient groups, but high enough
| to add up to problems if screening is too widespread.
|
| People didn't start worrying about this because it was
| "conventional wisdom", but because the data shows people
| actually dying.
|
| [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4878445/
| bildung wrote:
| You assume that the treatment works and has no side
| effects, I think that is the main source of
| misunderstanding.
|
| A great example is prostate cancer. It often gets detected
| now, people are informed they have cancer, but most often
| the correct answer is "watchful waiting", i.e. no
| treatment, probably forever. But people now know they have
| cancer, and are frightened, because cancer, and thus press
| for treatment. But this comes with a 10-90%(!) chance of
| incontinence and 50-90% chance of erectile dysfunction -
| for a cancer that most probably wouldn't have caused them
| bigger problems for their whole life.
| sbelskie wrote:
| I'm not sure I understand what you mean. It seems like
| you're framing my motivation as not wanting people to know
| that they are sick and being willing to trade peoples lives
| to achieve that outcome, which I don't think is at all what
| my above comment says.
| radu_floricica wrote:
| It is how I understood it, sorry about that. What did you
| mean?
| dabbledash wrote:
| The idea is that treatment also has risks and false
| positives are an issue.
|
| If you gave a mammogram to every 20 year old woman, you
| would end up doing a large number of unnecessary biopsies
| and you'd find almost no real cancer. In the end, you'd
| lose more people than you would save.
|
| Or that's the idea. I'm no expert in this but it makes
| sense to me conceptually.
| JumpCrisscross wrote:
| > _If you gave a mammogram to every 20 year old woman,
| you would end up doing a large number of unnecessary
| biopsies and you'd find almost no real cancer_
|
| If you gave a mammogram to every 20-year old, you
| wouldn't do a biopsy when you got a positive. You'd
| increase monitoring and maybe suggest lifestyle changes.
| The same way we don't immediately catherize everyone who
| comes back with high cholesterol.
| vidarh wrote:
| If you gave a mammogram to every 20-year old, you'd
| _cause_ a significant increase in cancers:
|
| https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4878445/
| refurb wrote:
| Yup. Let's say the test shows "very likely" for pancreatic
| cancer.
|
| Now you do imaging. Ok, nothing there? Now what? Biopsy?
| That's general anesthesia now and costly (for the patient or
| govt). Biopsy is negative. Now what? Start chemo? Watch and
| wait? For how long? Do a biopsy every 6 months?
|
| None of these tests are 100% accurate. If broadly used, a
| false positive of 0.1% will result in tens of thousands
| getting unnecessary testing.
| postingawayonhn wrote:
| > Now you do imaging. Ok, nothing there? Now what?
|
| Put the patient on a more frequent screening schedule
| (blood tests and imaging) to pick up any growth.
| someguydave wrote:
| exactly, this screening is an invitation for overtreatment.
| kokey wrote:
| I think for pancreatic cancer early detection just means it
| gives you more time to enjoy a slightly longer bucket list.
| For bowel cancers however, this could potentially buy many
| extra years since it's currently difficult to detect early.
| refurb wrote:
| One reason why pancreatic is so fatal is it doesn't tend
| to get diagnosed until quite late, so this test could
| help here. But really early cancer (no identified mass)
| is more of a watch and wait thing.
| hannob wrote:
| The reason this is not happening isn't a technical one. It's
| that people with a medical background will tell you this isn't
| a healthy utopia, it's a nightmare.
|
| Medical tests are complicated. They often have significant
| false positive and false negative rates. Testing people at
| scale increases the number of people with wrong test results
| and can cause harm if you start treating people based on wrong
| test results. The more healthy people you test the more false
| positives you get.
|
| The goal of evidence based medicine is to use tests when they
| can help. It's not to test as many people as possible. This is
| reasonable. You want to improve patient's lives. Whether or not
| a test is improving patient's lives is often not easy to answer
| and has to consider many things.
| axxto wrote:
| The point of this is not that you get a definitive diagnosis;
| it's just a somewhat reliable marker on whether you may need
| to be concerned and get more accurate (but more harmful)
| imaging or invasive tests to rule out something.
| colinmhayes wrote:
| You don't see how causing many people to worry and get
| invasive screening per person you have a true positive for
| is a worse outcome?
| dangerlibrary wrote:
| You only need one false positive test result that ends up
| with a colonoscopy to understand how costly and
| uncomfortable these errors can be.
|
| (I'm using an uncomfortable and illustrative example, but a
| colonoscopy is honestly pretty safe and boring as invasive
| clinical diagnostic procedures go)
| theptip wrote:
| Perhaps a better example than you intended -- recently
| colonoscopies are being considered more risky as a
| regular screening tool, because the procedure itself can
| result in harms, including (rarely) death. Not an expert
| here, but it seems they are still used in a fairly wide
| age group, but the recent trend is to be more cautious
| about their usage, as particularly for older patients
| they are more risky vs. the potential benefits. [1]
|
| However I think this concern would be reduced if we had
| better first-line screening like the tests in TFA; the
| harms come from using a relatively-risky assay like
| colonoscopy for regular screening in healthy individuals,
| whereas if we had better noninvasive screening, the
| colonoscopy could be reserved for patients where there's
| a higher probability of a positive diagnosis.
|
| [1]:
| https://jamanetwork.com/journals/jama/fullarticle/2529486
| bcrosby95 wrote:
| > somewhat reliable marker
|
| For the USA...
|
| Something around 1.8 million people are diagnosed with
| cancer per year. At a 50% false negative rate, all else
| being equal it would detect 900k of those.
|
| And all else being equal, at a 0.5% false positive rate, if
| it were used as suggested it would incorrectly diagnose
| cancer in around 1.6 million of the population.
|
| So around 60% of the people it says has cancer wouldn't
| have cancer. I guess it depends upon what you mean by
| "somewhat reliable".
| Gatsky wrote:
| Note this test is about early detection, not prevention. If
| your pancreatic cancer is detected early, you will still need
| to have your insides rearranged to get it out.
| plank_time wrote:
| There is no early detection for pancreatic cancer. So we
| don't know what we can do yet. Right now by the time we
| detect it, we are dead.
|
| An entire generation of early detection might create new
| methods to treat it. We don't know what we don't know.
| aembleton wrote:
| > There is no early detection for pancreatic cancer
|
| The third paragraph of the article says otherwise. Do you
| have some knowledge about this test not working?
| [deleted]
| junon wrote:
| "Preventative care" refers to the field of medicine called
| preventative medicine/care/health, which specifically aims at
| making regular checkups and other monitoring facilities free
| and accessible in order to improve health via early-
| detection.
|
| Oftentimes, doing these sorts of things lowers your insurance
| premiums or makes costs lower if something does happen (not
| always, but sometimes). These sorts of things are also
| generally free as it costs the insurance company less in the
| long run if you're doing them frequently enough.
|
| Perhaps a bit of a misnomer, but "preventative care" doesn't
| necessarily mean medicinal prevention of any sort.
| dannyw wrote:
| That's a critically better health outcome though. It's like
| fixing a corruption bug when you detect it on one server,
| versus finding out there's corruption in every shard and all
| of your backups.
| jacquesm wrote:
| > That's a critically better health outcome though.
|
| Not necessarily. It depends on how old you are, what your
| genetic make-up is, whether the cancer is growing rapidly,
| whether it has easy access to other organs to spread to (or
| has already begun to do so) and so on. It's not a binary
| thing.
| carlmr wrote:
| Ransomware infecting one machine or all machines including
| backups would also be a good analogy.
| petra wrote:
| There's a big difference(in success rate, in damage to the
| body, in costs) when treating a tumor at 1 cubic mm size or
| less, versus a big tumor, versus a malignant tumor.
| matheusmoreira wrote:
| > Why can't we observe ourselves medically and analyze that
| record for early signs of trouble before it becomes serious?!
|
| Maybe one day we'll have cybernetic implants that can
| constantly monitor our health. Hopefully it won't turn into a
| privacy nightmare.
| TaupeRanger wrote:
| Actually you don't want this, and you are describing a
| nightmare scenario that everyone who studies health policy
| understands all too well. Mass screening of healthy people will
| result in extreme iatrogenics and unnecessary psychological
| damage and stress (which leads to physical effects as well),
| not to mention overwhelming the medical system.
|
| The fact is that many things that _could_ be detected will
| _never_ result in symptoms or other noticeable problems.
| Further, for many things that _can_ be detected we can 't
| really do much about, so by detecting it early you are just
| reducing the amount of life they have left without worrying
| about their disease, or causing unnecessary treatment (which
| includes unnecessary damage, cost, stress, etc.)
| handmodel wrote:
| I'm not sure.
|
| I weight myself everyday. Some people tell me not to do that
| but its honestly pretty good at keeping me in check and
| _because_ I weigh myself everyday I know that sometimes I
| just get super bloated and put on four pounds of water and it
| will be gone in a couple days. When you get more data you
| learn to adjust how you interpret it and make better
| decisions.
|
| Likewise, if getting a false result 50% of the time becomes
| common (this assumes we never improve the tests) then people
| will know to adjust their priors. After all - I've had to go
| to specialists a few times for extra tests. I wouldn't say we
| ban those.
| shard wrote:
| Yes.
|
| I meticulously tracked every calorie I ate for several
| months. Now I know how much of different types of food is
| how many calories, how many calories I eat per day, and
| most importantly what my different hunger levels mean in
| terms of the number of calories ingested. Combined with my
| weight tracking, which tells me my set weight / weight
| variance over a day or several days / food intake to gain
| or lose a certain amount of weight, I can easily control
| portions to hit my weight goals without thinking about it.
|
| I would imagine more health data would allow me to optimize
| in this fashion as well. If I can correlate health markers
| to my lifestyle often and directly, I can make better and
| more informed choices. Advocating against easy access to
| health data because some people can misuse it is the same
| kind of nanny state thinking that says encryption shouldn't
| be available to the masses because criminal enterprises can
| use it to hide their activities.
| treeman79 wrote:
| I had a mystery illness. Spent hundreds of thousands on Er
| visits only to find it's was a pair of fairly common
| conditions acting together. Blood work tests exists for both.
|
| A deep round of blood testing would have saved everyone a lot
| of time and money and suffering.
|
| Or I could have waited many years until the organ damage was
| so extensive that diagnosing was easier. Oh wait, that's what
| ended up happening.
| LightMachine wrote:
| This mindset kills more people than Hitler. Have a good day.
| throwawaynotmd wrote:
| The argument you're making has always bothered me because
| it's hiding the ball.
|
| If finding something that otherwise carries no symptoms is
| best left untreated, then the fact that you found it should
| make no difference to the decision. The doctor should say
| that the best course of action is to do nothing. More
| information can never be harmful. If you know information is
| best not acted on in the abstract, then you also know you
| should not act on it in particular.
|
| So what you really mean but have left unspoken is one of two
| things.
|
| First, that doctors are untrustworthy people who make
| recommendations and decisions based on concerns other than
| their patient's wellbeing, such as covering their asses from
| lawsuits or making more money.
|
| But rather than fix _that_ , you would rather keep patients
| more ignorant and away from the doctor in the first place.
| Which actively harms people who do have honest doctors. That
| is, your approach of not testing hurts people with honest
| doctors to protect people with dishonest doctors.
|
| Or second, if you take dumb patients as the problem, you are
| willing to hurt people with good decision making ability (who
| would heed their good doctor's advice to leave the possible
| ailment untreated) so you can protect people with bad
| decision making.
|
| Because many times, these tests will uncover things that
| obviously need treatment. They will save many lives. But
| because more stupid people will hurt themselves, then no one
| should have access to them.
|
| The political and moral assumptions built into these
| positions are immense and yet the medical field tucks those
| away and pretends that this is just a purely scientific
| truth, that someone running more harmless tests is actually
| inherently harmful.
|
| That is a lie! And a very nasty one at that.
| [deleted]
| CWuestefeld wrote:
| _if you take dumb patients as the problem, you are willing
| to hurt people with good decision making ability (who would
| heed their good doctor's advice to leave the possible
| ailment untreated) so you can protect people with bad
| decision making._
|
| It seems like we've made this decision with covid-19. Dr.
| Fauci has been canonized, but we know that he's been
| intentional misleading the public through misinformation
| (starting from telling us that masks aren't effective in
| order to preserve the supply for medical providers, and
| later mis-stating herd immunity numbers to manipulate
| people into getting the behavior he wanted).
| bryan0 wrote:
| > More information can never be harmful.
|
| This is an extremely naive viewpoint and in some situations
| quite dangerous.
| throwawaynotmd wrote:
| I should say, if you know ex ante that certain results
| are not worth acting on, then when you actually get those
| results ex post, you should ignore them just the same. So
| actually running a test cannot formally be the problem.
| TaupeRanger wrote:
| That is not how medicine works, especially with cancer.
| Very often we simply don't know whether or not to
| "ignore" something. But the harms of _knowing_ are not
| zero, and therefore screening can itself be a net
| negative. That 's why a well powered RCT is required to
| say whether it benefits patients or not.
| grahamburger wrote:
| Isn't the only way to learn what things we can ignore and
| what things we can't ignore to do a lot more testing? Is
| there a better way to learn that? It seems like having a
| lot more data from tests is the kind of thing that would
| have some short term harm but massive long term benefits.
| throwawaynotmd wrote:
| We have a more detailed exchange going on elsewhere in
| this thread, with my latest comment, addressing your more
| detailed points, here:
| https://news.ycombinator.com/item?id=27630947
| ganafagol wrote:
| > More information can never be harmful.
|
| That statement alone shows blatant ignorance of basic
| properties of the human psyche which makes reading the rest
| of your long reply rather pointless, as thought-through as
| it might have been from your perspective.
|
| Humans are not the perfectly rational machines you seem to
| make them out to be. You need to deal with people in the
| real world, not some dream utopia that does not exist.
| Fomite wrote:
| "More information can never be harmful."
|
| In my particular field of biomedical research, there has
| recently been a push for "Diagnostic Stewardship" because
| more information has demonstrably been harmful to patient
| well-being.
| captainmuon wrote:
| I believe that's what the data says, but I have a really
| hard time reconciling it with common sense. More
| information is strictly better than less information,
| because you can always choose to ignore the extra
| information.
|
| I would say most medical decisions are made either due to
| statistics, or due to experience. What treatment has the
| highest chance of making the patient better, extending
| their life, or giving the best quality of life? You'd
| "just" have to adjust the tables for the new test.
|
| I mean in a contrived example, you could have the lab
| technician themself look up the numerical result (xyz >
| 100, abc < 10 whatever) in some table, and then there
| would be the rule to throw the result in the bin and
| report "don't treat" because this results in the best
| outcomes. I don't want to have all that extra diagnostic
| information, but I want my doctors to use it
| _conditionally_ to improve my treatment if possible.
| Jap2-0 wrote:
| > you can always choose to ignore the extra information.
|
| Can you?
|
| That is to say: you can try, but I don't think most
| people are very good at consciously choosing not to think
| or worry about something that they know, if that's even
| possible.
| Fomite wrote:
| "I believe that's what the data says, but I have a really
| hard time reconciling it with common sense."
|
| Can you see why some people might be hesitant about
| basing medical treatment on "That's what the data says,
| but it doesn't conform to my priors, so it's probably
| wrong"?
|
| People are terrible at ignoring information. Clinicians
| are people. We know this.
| throwawaynotmd wrote:
| It's not enough to say it's harmful. _How_ is it harmful?
| A blood test, for example, cannot be inherently harmful.
| (Okay, no more harmful than drawing blood). So it must be
| about what people then decide to do based on that test.
| That's what my post is about.
| vidarh wrote:
| Do enough of them, and even basic blood tests cause harm.
| Infections happen. Rupturing veins happens.
|
| If your tests are for conditions that are rare enough,
| and where early detection does little enough to improve
| outcomes, even a tiny risk like that becomes a problem.
| Fomite wrote:
| But _vanishingly rarely_ are diagnostic tests given and
| then the results ignored. That 's not how consumers of
| healthcare nor clinicians work.
| ArtRichards wrote:
| If thats how you feel, I invite you to slapsgiving this
| year! Exactly 18:32 on the eve of Thanksgiving.
| TaupeRanger wrote:
| Lots of problematic assumptions in your reply.
|
| >If finding something that otherwise carries no symptoms is
| best left untreated, then the fact that you found it should
| make no difference to the decision. The doctor should say
| that the best course of action is to do nothing. More
| information can never be harmful.
|
| Absolutely and demonstratively false. There is an entire
| field of health policy that destroys this harmful idea.
| First of all, just because something doesn't carry symptoms
| NOW doesn't mean it won't carry symptoms LATER, but doctors
| can't always predict this and aren't perfect decision
| making machines. Many times the patient will push them for
| further tests and treatment (or the doctors will advocate
| for it to ease the mind of the patient) which leads to
| potential harm from unnecessary treatments. And this is
| just ONE of the ways patients are harmed by unnecessary
| screening. There is also the psychological damage of having
| a condition you wouldn't have otherwise known about, and
| living with that knowledge (take aneurysms for example).
| Psychological stress has a real physical toll on the body.
| Then there's the COST associated with unnecessary screening
| and treatments, which (especially in the US) can run into
| the thousands quite easily for even simple interventions as
| a result of unnecessary screening.
|
| Even after that, a screening process can also find
| something that _could_ be bad, but in some patients doesn
| 't actually decrease their lifespan or quality of life. If
| we have no way of adjudicating between these cases or
| predicting which cases will end up bad if left untreated at
| the present moment, what do you think will happen? People
| will ask to be treated anyway, and iatrogenics will rear
| its ugly head.
|
| You cannot ASSUME that screening is automatically good. It
| must PROVE itself as such in a randomized clinical trial.
| This trial must show that people live _longer_ and /or
| _better_ as a result of this intervention. In many well
| documented cases, this turns out NOT to be the case, which
| entirely destroys your original rebuttal.
| skybrian wrote:
| I have no expertise here but I worry that these trials
| are studying the decision-making processes around how
| people decide to use the information from these tests,
| rather than the tests themselves.
|
| How people use information varies, so the data might not
| have external validity - it's culture specific, and
| cultures differ. Cultures can also change through
| accumulated experience.
|
| So do the people studying these things try again with
| different and possibly better decision-making, or do they
| conclude that the test itself is no good?
| TaupeRanger wrote:
| That is a very important point. This is why multiple
| studies are needed that across time, location, culture,
| etc. The more data a doctor has the better decisions they
| can make for their specific patients.
| throwawaynotmd wrote:
| > _Many times the patient will push them for further
| tests and treatment (or the doctors will advocate for it
| to ease the mind of the patient) which leads to potential
| harm from unnecessary treatments._
|
| > _People will ask to be treated anyway, and iatrogenics
| will rear its ugly head._
|
| I just want to say that you are in agreement with my
| position here.
|
| Your point about psychological problems is interesting,
| but as long as people know what they're signing up for,
| it's okay. Some people aren't prone to anxiety. Why
| should they pay the price because other people are? Part
| of my original point was that implicit in your argument
| is that people capable of handling it should be denied
| something because more people incapable of handling it
| can't be stopped from hurting themselves. I think many
| people do not agree with that moral reasoning, so medical
| people hide it behind objective looking statistics.
|
| And as for cost, I don't take any arguments from medical
| people about cost seriously. The reason why costs are so
| high is because doctors and the medical field as a whole
| run a massive protectionist racket to keep the supply of
| medical professionals low.
|
| How fresh of them to say that because they've limited the
| supply of medical resources to enrich themselves,
| _patients_ must pay by having less access to care.
| novok wrote:
| I think once you become a doctor, you quickly realize
| that a large amount of the population do not have the
| temperament to deal with 'maybe' bad news. Many are not
| the 135 IQ %1 of the population with a low anxiety
| personality who accept that they will eventually grow old
| and die, which happens to coincide with many engineering
| types on HN.
| pie420 wrote:
| Lol, i would argue that engineers, many of whose primary
| job function is to imagine worst case scenarios and
| engineer around those to prevent accidents, data loss,
| etc. Are the exact type of people that are prone to
| hypochondria. It's not about growing old and dying, it's
| about ignoring a stomach ache for a couple months and
| then being told you have terminal cancer, and then living
| with the regret of "if only I got it checked out
| earlier".
|
| In the engineering world, you are almost always rewarded
| for being extra safe and testing, fixing, and
| investigating anything that might seem a little off. If
| you do blood tests, MRIs, and cancer screens for every
| mole, cough, and stomach pain, you will go insane and
| develop hypochondria.
| novok wrote:
| I guess depends on the mental counter response those
| engineers take. Because you have to think about every
| possibility, you create a counter temperment that doesn't
| implode thinking about every possibility.
|
| Some might go the other way, and their anxious
| personality might help them think about everything, but
| also make them a stress case.
|
| I think the first type tends to last longer in the
| industry, at least for my coworkers.
| exdsq wrote:
| Your point about a protectionist racket doesn't hold for
| countries in the EU which have the same rules around
| research data and patients
| fierro wrote:
| you're conflating "pushing for further tests" with
| "pushing for further treatment.' IMO, everyone should be
| entitled to as much data accumulation as they want.
| Insurance companies can set reasonable thresholds, but if
| I want to pay out of pocket to get bloodwork done, that
| should be easy to get.
|
| Whether or not a doctor prescribes/advises a certain
| treatment is still firmly in their domain. The amount of
| biomarkers/biological evidence a patient has shouldn't
| sway a doctor's decision to alter a treatment plan. As a
| reasonably smart non-medical professional, I would rather
| have more data than less data, and it's paternalistic and
| a little condescending to say "no, you shouldn't actually
| take diagnostic tests because 'having that information
| might freak you out'"
| fallingknife wrote:
| > but doctors can't always predict this and aren't
| perfect decision making machines
|
| So mass screen healthy people, collect the data, run
| models, and get better at it. People like you would
| rather not try, and this is the same reaction I get from
| doctors. Applying the same tech that we use to improve ad
| targeting to disease prediction is a no brainer to anyone
| whose cushy job doesn't depend on the current medieval
| state of medical technology.
| rackjack wrote:
| Same vibe as "I would just simply..."
|
| What do you think the entire medical, pharmaceutical,
| bioinformatic, etc. industries have been doing for
| decades? Are you really so arrogant to think that other
| people are too lazy and stupid to think of your brilliant
| idea and that you are simply more intelligent than
| everybody else? Do you really think people haven't been
| trying?
| epicureanideal wrote:
| > What do you think the entire medical, pharmaceutical,
| bioinformatic, etc. industries have been doing for
| decades?
|
| Well, let's remember that the AlphaFold team at Google
| solved the protein folding problem with a relatively
| small team in a relatively small number of years after
| extremely large, well funded companies whose primary
| business was drug development failed to do so for
| decades.
|
| So yeah, it's been demonstrated to be possible that the
| current leaders in a field might be significantly less
| capable than a different team.
| timy2shoes wrote:
| > let's remember that the AlphaFold team at Google solved
| the protein folding problem with a relatively small team
| in a relatively small number of years after extremely
| large, well funded companies whose primary business was
| drug development failed to do so for decades
|
| Did they though? They did extremely well at CASP14, and
| much better than competing groups. But does this solve
| protein folding? Deepmind's marketing department would
| have you think so, but for those of us that work in the
| field we know that this is not the case.
|
| Furthermore, does protein folding solve the relevant
| problems of drug design? It solve the forward problem,
| given an amino acid sequence predict its 3d structure.
| But for drug design we need the inverse problem, given a
| specified structure predict an amino acid sequence that
| produces that structure.
| wxnx wrote:
| There's confounding here that you're ignoring. For
| reference, I'm a machine learning research scientist who
| started in bioinformatics, initially lured by the
| possibility of a machine learning solution to the protein
| folding problem.
|
| Google's research arm has made leaps and bounds in a
| particular field (deep learning) and then managed to
| apply it successfully to a very, very hard problem
| (protein folding). That other companies failed to adapt
| Google's successes in deep learning faster than Google is
| not surprising at all to me.
|
| One might argue that the impact of academic-big pharma
| collaboration (in the form of funding for research
| projects related to CASP) is what enabled a company like
| Google, with no independent desire to collect the massive
| amounts of wetlab data required to evaluate or develop a
| tool like AlphaFold, to even participate.
|
| More importantly, AlphaFold hasn't really solved the
| protein folding problem well enough for drug development.
| So, the entire debate might be moot.
| kilotaras wrote:
| > Are you really so arrogant to think that other people
| are too lazy and stupid to think of your brilliant idea
| and that you are simply more intelligent than everybody
| else?
|
| Here's a report of a person whose wife had seasonal
| affective disorder. He
|
| - deduced that a powerful enough lightbox should be able
| to cure SAD - didn't find any examples of such treatments
| in literature - spent $600 to build "LUMINATOR" - "And as
| of early 2017, with two winters come and gone, Brienne
| seems to no longer have crippling SAD--though it took a
| lot of light bulbs, including light bulbs in her bedroom
| that had to be timed to go on at 7:30am before she woke
| up, to sustain the apparent cure."
|
| https://www.lesswrong.com/posts/zsG9yKcriht2doRhM/inadequ
| acy...
| function_seven wrote:
| If they aren't mass collecting this data in the first
| place (for the reasons outlined above), then how _can_
| they be doing this?
|
| Or, if they are doing this from quality samples of the
| population, then we have data to show that, for example,
| "Yes, Mr. Function Seven, your scan shows elevated levels
| of Widget-5a enzymes. This is often a precursor to Gadget
| Cancer, but 30% of the population shows this elevation,
| while only 1% develop the cancer. It's best to do nothing
| at this time unless we see further elevation. Have a good
| day, see you next year"
|
| So either we have this data and we can give accurate
| advice, or we don't have this data because we're afraid
| of over-diagnosing non-problems.
|
| I understand the fear, but it's still burying one's head
| in the sand to not even look.
| rackjack wrote:
| They are mass collecting the data. They have more data
| than they know what to do with. Bioinformatics abuses
| data science at levels comparable to Google and Facebook.
|
| They are getting quality samples from the population. But
| it's not a simple as "high enzyme = maybe good chance of
| cancer". How are you going to get those enzymes from
| their blood in a way that can be applied to the general
| population? Before that, how do you know there's not
| confounding factors (of which they are a LOT)?
|
| > So either we have this data and we can give accurate
| advice, or we don't have this data because we're afraid
| of over-diagnosing non-problems.
|
| It's not that easy.
|
| Look at this pathway: https://www.pathwaycommons.org/guid
| e/workflows/rna_seq_to_en...
|
| From here: https://www.pathwaycommons.org/guide/workflows
| /rna_seq_to_en...
|
| This is what people think the activation of genes is.
| What they THINK the activation of genes is.
|
| Note the following:
|
| - They don't know all the genes. They are constantly
| identifying new ones. The number of gene pathways people
| are pretty sure are complete is small. I don't know if
| this one is one of the "pretty sure" ones.
|
| - Gene pathways are not just complex in terms of size,
| they are also non-linear. This is not a computer program,
| this is a horrible biological mess where biological
| components constantly and probabilistically emit
| chemicals.
|
| I don't even think that the pathway I gave you is super
| representative - it doesn't feature the ridiculous non-
| linearity and uncertainty that many pathways at the
| bleeding edge have. They can get much worse.
|
| People are not burying their heads in the sand. They are
| trying their almighty to dig up from bedrock and reach
| the sky.
| jghn wrote:
| > Bioinformatics abuses data science at levels comparable
| to Google and Facebook.
|
| To give people a sense of this, it is not unheard of for
| large scale bioinformatics platforms to set off alarms
| and/or zone-level capacity issues with the large cloud
| providers.
| hebrox wrote:
| Would you say that they could collect way more data?
| deeviant wrote:
| > Are you really so arrogant to think that other people
| are too lazy and stupid to think of your brilliant idea
| and that you are simply more intelligent than everybody
| else? Do you really think people haven't been trying?
|
| I find it hard to believe I'm reading this sentiment on
| HN. Do you realize nearly any disruptive idea has do the
| "arrogant" thing you are speaking off.
|
| Big companies go out of business all the time, industry
| disappear or wane all the time, big companies/industries
| with lots of smart people do stupid stuff on the regular.
| Characterizing the desire to do something other than
| status quo as "arrogance" is just the bottom of the
| barrel. I'm glad Semmelweis didn't think the way you do.
| jjeaff wrote:
| I didn't understand their comment to mean that at all.
| It's not arrogant to think there might be a better way.
| It probably is arrogant to think that the better way is
| actually really simple and easy to implement.
|
| Arrogance definitely can play a big role in success of
| many startup entrepreneurs. Because they think the answer
| is simple and their arrogance shields them from not
| trying. So they go down the road and find out the
| solution is actually quite complicated, but a small
| percentage succeed in accomplishing the goal.
|
| But it's still arrogance, nonetheless.
| avion23 wrote:
| > Are you really so arrogant to think that other people
| are too lazy and stupid to think of your brilliant idea
| and that you are simply more intelligent than everybody
| else?
|
| Not OP, but yes, I do.
|
| I've had some runins with the health system. At least the
| parts that I've seen are worse than the dark ages.
| Especially endocrinologists have absolutely no clue what
| they are doing. The ones I met don't even have
| superficial knowledge about their full-time job which
| they've performed for ~20 years.
|
| And yes, this sounds arrogant. I've tripple checked
| whether I'm just tripping. Their knowledge is not simply
| outdated, but never correct to begin with.
|
| I think it's a cultural problem which shows in a lot of
| areas. Medicine doesn't value human life as much as f.e.
| air transport
| rackjack wrote:
| You're talking about praxis, we're talking about
| research. I agree the praxis can be pretty bad, but in
| regards to the above commenter's remarks on why people
| don't just simply collect data and apply it, medical
| professionals simply cannot try out new treatments the
| way they are suggesting.
| jghn wrote:
| To go further, a large issue/distraction in biomedical
| research has been Big Tech types coming in assuming that
| the roadblock all along has been lack of smart
| computational people in the process. I will not name
| names, but have seen so many instances of personal tech
| heroes coming in & claiming the underlying problem was
| that some of the brightest computational I've ever
| encountered simply didn't know how to computer.
|
| Nothing could be further from the truth. People coming in
| to "disrupt" only add noise. Eventually those people
| either understand this and put the effort in to
| understand the domain or they wander off.
| Robotbeat wrote:
| While it's absolutely true that naive non-experts can end
| up adding a lot more heat than light, I've also seen non-
| expert people come into stagnant domains and absolutely
| completely transform and improve upon the state of the
| art.
|
| I am skeptical of the "more data is bad" meme of
| screening hesitancy. It cannot be scientifically true in
| the strictest sense, and to the degree it's an accurate
| assertion, it really seems to reveal an unscientificness
| to how screening data is used today in practice rather
| than that in principle more data is bad.
| jghn wrote:
| In a perfect world you're right. What it's getting at is
| that screening itself isn't very good in the grand scheme
| of things, and thus the negatives of extra screening can
| be argued to be worse than the extra screening. Whether
| or not that's true, well that's another matter.
|
| The issue in this subthread was the notion that the only
| thing between the current state of affairs and high
| quality screening is a bit of disruption. The problem is
| hard, smart people are working on it, more smart people
| are always welcome, it'll still take a while.
| vidarh wrote:
| It's not that more data is bad.
|
| It's that 1) sometimes collecting the data itself is
| harmful at scale. E.g. mammography can _cause_ breast
| cancer, or cause it to spread. 2) the patients actions as
| a result of the data can, and does at sufficient scale,
| cause further harm.
| vidarh wrote:
| We _have done this_ for e.g. breast cancer, and that is
| exactly why people are cautious now, because we have real
| data on the harm overtesting can cause. That doesn 't
| mean it should never be done, but that it needs to be
| approached with care.
| sjg007 wrote:
| Prostate cancer as well.
| TaupeRanger wrote:
| You are assigning beliefs to me that I do not hold. As I
| said, we would need a solid randomized controlled
| clinical trial to determine whether any particular
| intervention actually helps patients live longer and/or
| better. That's the only way we know. So go ahead and
| collect data, do an RCT, and let us know how it goes.
| iNane9000 wrote:
| The problem with this and the nnt gatekeeping is that
| personalized medicine will always require stepping away
| from massive double blind randomized placebo controlled
| multiple meta study levels of evidence. From a patient
| perspective it feels a lot like economics largely
| determine medical outcomes.
| exdsq wrote:
| If you look into QALYs it does - at least in terms of
| policy over healthcare choices
| m3kw9 wrote:
| " If finding something that otherwise carries no symptoms
| is best left untreated, then the fact that you found it
| should make no difference to the decision."
|
| This is easy to say but hard to do, just need to imagine
| throwawaytcp wrote:
| If I can step in with a personal anecdote: I was diagnosed
| in my late 20s with papillary thyroid cancer.
|
| PTC is a very survivable cancer, with a near-100% survival
| rate (death usually only occurs in rare cases where the
| disease is diagnosed very late, the progession is atypical,
| or there are comorbidities at play). It is very easy to
| screen for and diagnose: a neck ultrasound identifies
| thyroid nodules, and if the nodules look suspicous they are
| biopsied in a 20 minute procedure performed under local
| anaesthetic.
|
| Treating papillary thyroid cancer is also relatively
| straightforward, as far as cancer goes: depending on the
| size of the lesion and the features, either half or all of
| the thyroid gland is removed surgically. In cases where the
| whole gland is removed (which is the majority), the patient
| is given a course or two of radioiodine therapy to nuke
| anything left over, and in many/most cases, it's a done
| deal.
|
| The vast majority of thyroid cancer survivors have to take
| thyroid replacement hormones (all patients who had the
| whole gland removed have to do this, and about half of
| patients who only had half the gland removed still need a
| small dose to keep up). I'm relatively lucky: the oral
| hormone seems to work just fine for me. I take a pill every
| morning and then go about my day. I will need to do this
| for the rest of my life, but hey, that's life.
|
| However, there's a substantial minority of patients who
| aren't so lucky: even with oral hormone replacement, they
| suffer from long-term sequelae including weight gain, low
| energy, brain fog, hair loss, and other hypothyroid
| symptoms.
|
| And there lies the crux of the issue: it turns out that
| even with increased diagnostic capability (thanks to the
| ubiquity of relatively cheap ultrasound exams in clinical
| practice), the number of people dying from thyroid cancer
| has stayed pretty much flat for decades (mostly due to more
| aggressive types than papillary, such as medullary or
| anaplastic). Yet, we take out a lot more thyroids now.
|
| The reason this happens is pretty simple: if you see
| something, you have to do something about it. So you're
| removing thyroid glands from people where the cancer might
| never have actually grown big enough to be a problem, and
| then subjecting those people to a lifetime of hormone
| replacement therapy. Something like 10% of all cadavers at
| autopsy have thyroid cancer: it's a cancer that very
| commonly develops, but only becomes a concern in a few
| patients. As of now, we don't have a good way to
| differentiate between "thyroid cancer that's a problem" and
| "thyroid cancer that'll be fine."
|
| The clinical guidelines have changed a bit in recent years:
| if the cancerous nodule is really small, they'll now do
| "watchful waiting" and monitor the nodule to see if it
| grows. But you're still subjecting a patient to potentially
| many years of worry and regular testing. And good luck
| getting life insurance if you have a microcarcinoma! Yeah,
| it's _highly_ unlikely to kill you (especially when
| monitored), but try telling an insurer that.
|
| The medical profession is well aware of these concerns.
| That's why they avoid testing for thyroid cancer unless
| there are symptoms, such as thyroid hormone disturbances or
| a lump in the neck. If you were to make a thyroid
| ultrasound a regular test, you'd quickly overwhelm the
| system with cancer patients who probably never needed to be
| treated in the first place, and who may now have to get
| their thyroids removed and be dependent on pills for the
| rest of their lives.
| pie420 wrote:
| But this really just illustrates a lack of knowledge on
| our part. If we made thyroid screening a regular thing
| and invested $10B/year into diagnostics, analysis, and
| study, i guarantee you in 5 years or less we would have
| the most efficient, effective system for treatment,
| determining which microcarcinomas are bad, which ones to
| keep an eye on, etc.
|
| There simply isn't a profit motive right now, and there
| aren't a ought resources, so unprofitable, minor things
| like thyroid cancers and other, small, mostly non-fatal
| things fall by the wayside. If we could massively
| increase the resources and time spent of solving health
| issues, we'd have a lot better solutions. There only
| exist a certain amount of cancer researchers,
| oncologists, and clinical pharmacologists that can
| profitably exist. Lots of diseases will never be cured
| because there are too few people affected by them. Until
| we decouple medical progress from profit, there's a only
| a certain amount of progress we can make. Unfortunately,
| it seems like tying profit to medicine is the most
| efficient system we have, so it may be centuries till we
| get there
| Silhouette wrote:
| _Mass screening of healthy people will result in ..._
|
| But you don't know they're healthy. They might be sick but
| (so far) asymptomatic. That's why you screen, if you have a
| sufficiently accurate test available and you can make a
| useful intervention if the test gives a positive result.
|
| If we applied your argument consistently, we would abolish
| all cancer screening programmes, resulting in many extra
| deaths because early detection and treatment didn't happen.
| We'd stop checking up on heart health as people age,
| resulting in many extra deaths because people continued to
| live unhealthy lifestyles without realising what it was doing
| to them. We wouldn't be using rapid testing for COVID-19 to
| detect and isolate probable asymptomatic carriers who might
| spread the virus to others who wouldn't be so lucky. The list
| goes on.
|
| Good screening programmes save lives. It's as simple as that.
| Buttons840 wrote:
| > so by detecting it early you are just reducing the amount
| of life they have left without worrying about their disease
|
| I wonder if people would rather continue to live care free,
| spending most of their waking hours commuting and at work, or
| if they'd rather learn the truth and face the harsh reality
| that their time is about up and adjust their priorities
| accordingly?
| throwawayboise wrote:
| Nobody knows when his time is up. You could be hit by a
| truck on your commute to work.
|
| I would rather live my life as it comes, for whatever
| length of time fate has given me.
| daemonk wrote:
| I understand this argument. But if we separate out the mass
| screening/data-collection approach from its practical
| constraints (undue stress, overwhelm medical system), I think
| we can both at least agree that it is a correct direction to
| head towards? Or is the status-quo already as well optimized
| as it could be?
| BurningFrog wrote:
| _Iatrogenics_ is when a treatment causes more harm than
| benefit.
| AlexCoventry wrote:
| If we optimistically assume the claimed 0.5% false positive
| rate is accurate, and all of the US got tested annually,
| that's 1.64M false positives per year. Cancer.gov is telling
| me that approximately 1.8M USians were expected to get cancer
| last year. That's a positive predictive value of 52%. That
| still seems highly informative, to me; much higher than the
| PPV for mammography according to this (admittedly old) study:
| [1].
|
| Assuming the 0.5% FP rate holds (again, I know that's
| optimistic), would you still regard universal testing with
| this method to be harmful?
|
| [1] https://jamanetwork.com/journals/jama/article-
| abstract/40935...
| amelius wrote:
| Isn't this exactly why the headline reads "blood test good
| enough to be rolled out"?
|
| I.e., higher FP rate, and it wouldn't be rolled out.
| AlexCoventry wrote:
| IIRC, the actual article says they're going to do a large
| trial, with 150k people, and someone in the article
| expresses skepticism that the estimated FP rate of 0.5%
| is accurate, because so far it was tested in people where
| there's some evidence of cancer.
| dan-robertson wrote:
| Is that actually good though? It feels to me that there's a
| big difference between explaining the implications of a
| positive result to someone who understands bayes theorem
| and someone who doesn't.
|
| Another aspect of cancer screening is that detecting cancer
| earlier can improve key statistics like 5 year survival
| without affecting the actual disease in any way. Which can
| make screening sound more effective than it is.
| TaupeRanger wrote:
| Good question. The proof is in the pudding. Run a well
| powered RCT and if the intervention helps patients live
| longer and/or better, then we should consider using it! It
| will be hard to design a study that includes all possible
| detected cancers, but there are ways around this - perhaps
| we begin by studying those cancers that are most common and
| lethal, and go from there.
| plank_time wrote:
| Utterly wrong. You are conflating current technology like
| MRIs and CT scans that only detect lumps, to blood tests that
| detect CANCER.
|
| Yes, if every lump were treated and excised then it would be
| problematic. But CANCER is different. The only cancer that
| you might be able to leave alone is prostate because it grows
| so slowly. Everything else is a risk.
|
| And if we can treat cancer at early stage 1, then maybe
| people won't be as afraid of it because it has such a high
| rate of cure. We don't know that until we do it.
| fnord77 wrote:
| cells turn cancerous all the time and usually the body
| eliminates them without issue. this blood test is still
| going to hit all sorts of "false" positives, where it
| detects some cell that has gone cancerous that would have
| been eliminated anyway.
| jghn wrote:
| I'm far from expert but I don't think this would be a
| large concern. My understanding of CTCs (circulating
| tumor cells) is that they are shed by a growing tumor. A
| random weird cell doesn't seem likely to be turned up in
| a test like this. You need some amount of quantity to set
| off the proverbial alarm bells
| TaupeRanger wrote:
| You say "utterly wrong" and yet you clearly have no idea
| what you're talking about and have never even approached
| the field of health policy. Screening has to PROVE that it
| makes people live longer or better, just like any other
| intervention. It is not the case that screening is
| automatically good, otherwise we would be giving 20 year
| olds colonoscopies. Just because you find something,
| doesn't mean you've helped the patient, as anyone with a
| modicum of understanding in this field knows.
|
| Read this and learn something:
| https://www.bmj.com/content/352/bmj.h6080
| jcims wrote:
| Your replies to folks in this thread contain the same
| hubris as the content of your message, which in turn is
| consistent with the hubris I've encountered in the
| medical community over the past five years.
|
| My wife went to urgent care twice in three months because
| of a pain in her side. She was turned away with cough
| medicine. She finally went to the ER where a CT scan
| revealed massive tumors in her abdomen that had gone
| undetected for likely years. Genetic and semi-annual
| CA125 screening could yield quite a few false positives,
| but combined with her physical symptoms she may have had
| more cause to press at an incomplete conclusion and
| possibly could have had a different outcome. She
| underwent nearly $2M in medical procedures over the
| course of 26 months and died at 45 years old last year.
|
| A few years prior to that I was spring cleaning one day
| and found a glucose test kit at the house. I had the
| whole family test their blood glucose. My youngest was
| 240mg/dL. We waited a day and tested again, same thing.
| We took her into the hospital and they actually admitted
| her for two days because they had no idea what to do with
| a child presenting with Type 1 diabetes that hadn't gone
| into full DKA. That's harmful, gross, and embarrassing.
| And this is a major children's hospital that was recently
| in the top ten in the nation for endocrinology.
|
| In both of these situations, preventative screening could
| have or did have positive outcomes. I don't disagree with
| the effect that has been observed, but the conclusion
| being drawn from it is revolting to me. People should be
| permitted to make their own decisions about their level
| of knowledge of the state of their body. We only get one
| trip as far as we know, and I just find it unacceptable
| that people are willing to categorically deny diagnostic
| technology or bemoan its development because they they
| don't know how to support people trying to navigate the
| information it brings.
| plank_time wrote:
| Exactly. Also my sincerest condolences to you and your
| family.
|
| The level of arrogance in these responses parroting what
| they've read in a paragraph online approaches that with
| what we saw early in the pandemic with masks.
|
| "Masks don't work! Fauci said so!" And the level of
| confidence they said it was shocking along with the self-
| righteousness.
|
| Yes, maybe people can't put on N95 masks properly... but
| maybe we can teach them? Is that so mind blowing? We
| teach people how to wash hands for 20 seconds, is it not
| so hard to believe you can't teach people to wear masks
| properly? Maybe make masks that are easier to put on?
|
| It's sad how people with no vision are Karen'ing people
| to not think ahead or think of the future. It's scary
| that it's happening on hacker news.
| plank_time wrote:
| We don't give colonoscopies to 20 years olds because it's
| an expensive, invasive test with a low rate of cancer. We
| don't give mammograms to under 40 year olds these days
| because the same and it's notoriously inaccurate.
|
| We give blood glucose level tests and cholesterol tests
| to everyone every year at the physical because they are
| cheap and easy to administer. Even though the effects of
| both may take decades to have any effect and have no
| correlation to ultimate death. It's about trade off of
| cost and convenience.
|
| If you detect pancreatic or colon cancer in a 20 year old
| patient via $1 blood test, that is immediately
| actionable. Cancer is ALWAYS actionable unless you're
| talking about prostrate which grows slowly. But even in a
| 20 year old, you would want to treat that but maybe not a
| 70 year old.
|
| And we've never had the ability to detect stage 1 cancer
| of the deadliest types of cancer. Imagine the new
| treatments that might save lives if we could.
|
| Honestly, the number of people here who think they know
| better and citing unrelated research is bordering on
| anti-maskers parroting the surgeon general saying masks
| don't work when they do.
| rwmj wrote:
| But this isn't the argument. The argument is about all
| the false positives you get when you mass-screen
| everyone. All those people then need to be further
| examined, overwhelming the medical system and causing
| distress for the individuals (who are, remember,
| perfectly well).
|
| I agree if we had a test that was 100% accurate
| (literally never gave a false result either way), only
| detected dangerous cancers, and cost $1 then that would
| be a game-changer, but the screening and tests so far are
| not that.
| fortran77 wrote:
| My father died from metastasized prostate cancer.
| tnel77 wrote:
| For every genuinely smart person on HN, there's a handful
| of Google warriors who hardly know what they are talking
| about. I guess that's not unique to HN, but it can be
| aggravating just how many commenters can be so "know-it-
| all" with their comments.
| TaupeRanger wrote:
| Try making an actual argument rather than simply
| attacking the attitude or character of the person you're
| responding to.
| tnel77 wrote:
| I was trying to agree with a comment I saw, but it
| appears I replied to the wrong comment.
| rackjack wrote:
| > It correctly identified when cancer was present in
| 51.5% of cases, across all stages of the disease, and
| wrongly detected cancer in only 0.5% of cases.
|
| If all 300 million Americans get blood tested each year,
| that is 1 and a half MILLION people who are falsely told
| they have CANCER. One and a half MILLION people whose
| life gets turned upside down, WRONGLY, due to a blood
| test -- at least, until they take a second one. Or a
| third one. Or maybe they get unlucky never learn they
| don't have cancer, and mess up their life treating a
| disease they don't have.
|
| Now, OBVIOUSLY not all 300 million Americans are going to
| get tested each year. But you are completely ignoring the
| ethical concerns surrounding telling literally .5% of
| those who don't have cancer that they have cancer, and
| the non-insignificant proportion of people who will never
| learn they don't have cancer (we NEED to consider even
| the "miniscule" probabilities at this scale), and that
| makes you seem like somebody who "think[s] they know
| better".
| sdg56 wrote:
| They will not be told they have cancer. They will be told
| they probably should check something out. Everybody
| already knows they might have cancer, having a negative
| blood test would be a huge relief.
| plank_time wrote:
| Do you think that technology doesn't improve over time?
| You are suffering from a fixed mindset, where you think
| people or technology is as good as it gets now and never
| improve.
|
| You should read up more on growth mindsets. People and
| technology aren't fixed. They change and improve over
| time.
|
| If people had your attitude about AIDS we would have let
| all AIDS patients die because "oh well nothing we can
| do."
|
| Luckily those with growth mindsets and optimism didn't
| listen to people like you and now AIDS patients take a
| single pill a day.
|
| The same could happen with cancer to, but not if people
| like you are in charge.
| TaupeRanger wrote:
| You are clearly confusing treatment with
| diagnosis/screening and should consider walking away from
| the conversation until you get a better understanding of
| the ideas being discussed here. Right now you're adding a
| lot of unnecessary noise with bad arguments.
| plank_time wrote:
| Nope. You are confidently wrong again.
|
| Early diagnosis means new ways of treating cancers like
| liver and pancreatic. You don't seem to understand this.
| Right now there is practically no treatments for either
| because it's detected so late. Maybe after 20 years of
| early diagnosis we can treat pancreatic cancer the same
| way we do others.
|
| Let me guess. You were telling people in early 2020 that
| N95 masks don't work.
| rackjack wrote:
| > If people had your attitude about AIDS we would have
| let all AIDS patients die because "oh well nothing we can
| do."
|
| No, if people had my attitude about AIDS they would say
| "Jesus Christ, don't tell 1 and half million people each
| year who don't have AIDS that they might have AIDS." I am
| talking about diagnosis, not treatment.
| shard wrote:
| Are you comparing that against the MILLIONS who get a
| correct diagnosis? I expect that the quality-adjusted
| life year total over all tested is higher with the test
| than without. Wouldn't that be worth it?
|
| I think this leans more towards the "the needs of the
| many outweigh the needs of the few" and less towards
| "tyranny of the majority".
| nmz wrote:
| Maybe I'm misunderstanding this but a 0.5% false positive
| rate and a 51% positive rate means that you still get a
| 50% TRUE positive rate instead of the current rate, which
| is 0%. And then after you can follow up with a test that
| is more accurate. Everything has an error rate, even
| pregnancy tests do, and nobody argues that we should not
| use pregnancy tests.
| JumpCrisscross wrote:
| > _One and a half MILLION people whose life gets turned
| upside down, WRONGLY, due to a blood test_
|
| Culture adapts. Getting a cancer diagnosis today is a
| huge deal because testing is infrequent, usually in
| response to a problem, and the diagnosis tends to be late
| and accurate. If 1.5mm healthy people get a false
| positive every year, the general response will be stress
| until a second test confirms a false positive.
|
| The lack of public trust in health policy doctrine, and
| the support for start-ups that can operate outside those
| channels, comes in large part from this type of thinking.
| rackjack wrote:
| > Getting a cancer diagnosis today is a huge deal because
| testing is infrequent, usually in response to a problem,
| and the diagnosis tends to be late and accurate.
|
| Getting a cancer diagnosis is a "huge deal" because
| getting cancer is one of the worst experiences a human
| can go through.
|
| Getting cancer carries the weight of imminent death,
| obviously. But some cancers can be cured with high
| survival rate, so what's the big deal? The deal is that
| these cures are often brutal chemotherapy or radiotherapy
| or whatever treatments that destroy your body, your
| sleep, your appetite, your ability to go to the bathroom
| yourself, your ability to do chores by yourself, your
| ability to do anything a normal human being can do. They
| DESTROY you.
|
| THAT'S the "huge deal". NOT the frequency. Cancer RUINS
| YOUR LIFE for the period you get treated, IF you survive
| the treatment at all, let ALONE the cancer. And you are
| proposing we tell sub-1.5 million people EACH YEAR that
| they might have to go through that, while STILL ignoring
| the proportion of the population that will never learn
| they have a false positive because they got unlucky
| (which, AGAIN, we need to consider, since even miniscule
| probabilities matter at this scale.)
|
| So until the day we figure out a way to make getting rid
| of cancer as easy as popping a pill (we're getting closer
| thanks to gene therapy, but patients may still receive
| the destructive treatments in the meantime), culture will
| not "adapt", it will remain a "huge deal", and we will
| keep "this type of thinking".
| tnel77 wrote:
| >Getting a cancer diagnosis is a "huge deal" because
| getting cancer is one of the worst experiences a human
| can go through.
|
| I've never been given a cancer diagnosis, but I'd imagine
| it's much, much worse to be told you have stage 4 cancer
| versus stage 1. As the other person stated, the culture
| would adapt and people would learn to not immediately
| sell their house and go on a Vegas bender just because a
| yearly preventative test said they might, possibly,
| perhaps have stage 1 cancer. If you are one of the people
| with a false positive, you schedule a follow-up and move
| on accordingly.
|
| Your position is anti-progress just for the sake of being
| against accidentally scaring a few people. Indeed, we
| should let more people develop cancer and discover it at
| a later stage due to a small amount of false positives.
| Not scaring a small amount of people is more important
| than revolutionizing cancer screenings.
| rackjack wrote:
| > I've never been given a cancer diagnosis, but I'd
| imagine it's much, much worse to be told you have stage 4
| cancer versus stage 1.
|
| It's bad all the way.
|
| > If you are one of the people with a false positive, you
| schedule a follow-up and move on accordingly.
|
| People already do schedule follow-ups and additional
| tests and second opinions when they get a positive.
|
| > Your position is anti-progress just for the sake of
| being against accidentally scaring a few people.
|
| No, it is cautiously ethical because:
|
| 1. You probably shouldn't tell sub-1.5 million people who
| don't have cancer that they have cancer
|
| 2. There are more false positives than you think, if you
| are suggesting regular blood tests
| ericd wrote:
| My impression is that yours is the consensus view in the
| medical community. But I think that what all these people
| are telling you is that they'd much rather have a much
| higher chance of a false positive stage 1 diagnosis than
| even a much lower chance of false negative diagnosis
| until they're at stage 4. And any positive result from
| this would obviously be couched in a doctor consult
| saying "if you have cancer, which this test doesn't
| definitively show, it's still very early, we're just
| going to keep an eye on it, we didn't get any
| confirmation from a chest x-ray or CT", etc
|
| And having a memento mori can be a positive thing.
| [deleted]
| mahkeiro wrote:
| Most stage 1 can be treated successfully with surgery
| alone, it's getting a late diagnosis that force you to go
| through a brutal treatment. If all cancer were detected
| in phase 1 it would not be seen as a "huge deal" anymore.
| JumpCrisscross wrote:
| > _these cures are often brutal_
|
| Heart disease is a huge deal. It ruins your life. (Maybe
| not in all caps.) Nevertheless, we regularly test for it,
| including with techniques with high rates of false
| positives. Few panic because almost everyone knows
| someone who got a false positive and didn't promptly keel
| over and die.
|
| If healthy adults are screened for cancer, there will be
| cultural memory of people who got a false positive. The
| response to a positive test result won't be chemo. It
| will be further testing, if non-invasive, or suggestions
| of lifestyle changes and increased monitoring of the
| suspected system.
|
| People aren't too stupid to understand an early test with
| a high false positive rate. People with family histories
| of cancer don't wake up every morning screaming. Some
| may. But barring everyone because some people will
| overreact is why orthodox health policy is losing public
| trust.
| rackjack wrote:
| I don't enough about heart disease treatment to comment
| on the degree it ruins your life.
|
| People already get further testing. People already get
| second opinions. In the time you are changing your
| lifestyle (a good option for helping treatment, I agree)
| and increasing monitoring you could already be
| progressing beyond treatability.
|
| You can argue about whether it's alright to tell sub-1.5
| million people each year who don't have cancer that they
| have cancer (I don't think it is, but whatever). But
| again you can't disregard the non-insignificant number of
| people who get false positives.
|
| edit: Actually, not "whatever". You probably shouldn't
| tell sub-1.5 million people each year who don't have
| cancer that they have cancer.
| UnFleshedOne wrote:
| > In the time you are changing your lifestyle (a good
| option for helping treatment, I agree) and increasing
| monitoring you could already be progressing beyond
| treatability.
|
| That's actually a very good argument for early testing.
|
| And needlessly scaring a some people into eating better
| and exercising more is about as bad as not screening them
| at all to avoid needless anxiety.
| burnished wrote:
| Hey, I can see this is emotional for you, but have you
| considered a world in which it is not telling this vast
| body of people "you definitely have cancer"? Something
| more like "we detected XXppm of [marker] which indicates
| we might need to do some more testing, can we talk about
| [risk factors]?".
|
| It just doesn't need to be as dire as what you are
| projecting.
| bluGill wrote:
| That this test is approved implies that it to some extent
| at least makes people live longer. There are a number of
| cancers that are easily treatable in stage one - but they
| have no symptoms then, and so often kill people because
| by the time it is discovered it is too late.
|
| False positives are a concern, but one that is
| manageable. People should get regular checkups, if
| something comes up we just do more testing as needed.
| rwmj wrote:
| It's approved to be rolled out to a medical trial. You
| can read what the journal says here: https://www.annalsof
| oncology.org/article/S0923-7534(21)02046...
| bluGill wrote:
| I'll stand corrected.
|
| Though that makes this discussion completely worthless -
| without trial results we have no idea if it is a useful
| test. Once we have those results we will know something
| about how useful/useless might be.
| [deleted]
| fortran77 wrote:
| My father died from metastasized prostate cancer.
| ska wrote:
| > ke MRIs and CT scans that only detect lumps, to blood
| tests that detect CANCER.
|
| You mean like the PSA test? It's pretty bad, in the scale
| of these things. It's used because there isn't a better
| screen, not because it is more specific.
| fallingknife wrote:
| I think it has more to do with how the kind of data collected
| from those mass screenings could be used to build predictive
| disease models that would put a lot of the guys making >=
| $300K to do a very poor job of keeping people healthy out of
| business.
| lhorie wrote:
| I think you're casting too wide of a net there. Just because
| you've detected something early doesn't mean you
| automatically need aggressive interventions like
| chemotherapy. The impact might just end up being a line in
| your medical record for the family physician to keep an eye
| on during yearly routine exams. Breast cancer awareness
| programs are a good example of early screening programs not
| being an exercise in mass hysteria. Some early symptoms for
| eye conditions only require periodic observation up until it
| actually becomes a problem. Etc.
|
| Perhaps it is true - in the US, anyways - that there's a
| tendency to overly prescribe more aggressive interventions
| (read: more expensive ones), but my understanding is that the
| US model is the exception, not the rule, when looking at the
| rest of the world.
| throwawayboise wrote:
| "The impact might just end up being a line in your medical
| record for the family physician to keep an eye on during
| yearly routine exams."
|
| And something to be on the back of your mind as a worry
| forever. I'd rather not know.
| vharuck wrote:
| >Breast cancer awareness programs are a good example of
| early screening programs not being an exercise in mass
| hysteria.
|
| This example also shows how screening can be recommended
| against because that's better for public health. The US
| Preventive Services Task Force (indirectly decides what
| Medicaid/Medicare covers) has different recommendations
| than the American Cancer Society for how often women of
| certain ages should have mammograms. USPSTF recommends
| against routine mammograms for women aged 40 to 49 if they
| don't have other risk factors. ACS recommends biannual
| mammograms start at age 45.
|
| The reason they differ is because of how they weigh the
| reduction in deaths against the harm of false positives.
| Routine mammograms will prevent breast cancer death, no
| doubt about it. But notice neither recommends routine
| mammograms for all women below 45, even though they
| accounted for over 10% of breast cancer diagnoses in
| 2014-2018[0].
|
| The math is tricky when comparing a risk of death against
| quality of life and economic costs. Public health is a
| matter of public policy as much as health.
|
| [0] https://seer.cancer.gov/statfacts/html/breast.html
| fierro wrote:
| this is a paternalistic point of view. People should be
| entitled to accumulate data about their own body -- any
| "negative" ramifications of this are personal problems.
| theptip wrote:
| While I agree with the point that you're making around
| employing caution against iatrogenics (with colonoscopies
| being a very good case study that one should make sure to
| understand before forming an opinion here, as you referenced
| in another point), I think you're overconfident in your
| prediction that this hypothetical scenario would be bad.
|
| I think your claim (based on sibling posts) is that in the
| current medical system, if we just added more screening, we'd
| not necessarily get net benefits. But I think that ignores
| the fact that, if we had cheap and high-resolution screening,
| we could fundamentally restructure many aspects of medical
| care. The BMJ article you linked in a sibling[1] notes that
| cancer screening may reduce cancer mortality but increase
| all-cause mortality. That's an unexpected and problematic
| result of getting referred to a cancer specialist that might
| not have (or be incentivized to care about) a wholistic
| picture of health when you screen positively for cancer. But
| if we had higher-resolution data, and conceptualized medicine
| as primarily preventive instead of curative, then it seems
| likely to me that overall mortality would be your target,
| we'd have richer data to be able to track that endpoint, and
| so we'd be more likely to catch the cases where an
| intervention caused unexpected harms (because we'd be
| tracking more indicators).
|
| In other words, the problem you're observing is that adding a
| bit more data to the current system can produce negative
| outcomes. But that problem would be fixed by adding even more
| data. (With the remaining question being, how much data would
| we need to add to reach the "net positive" regime?)
|
| I think you're arguing against a change that looks like a
| harm from the perspective of a local optimum that we're
| currently working towards, without considering the dramatic
| paradigm shift into another higher-utility region that would
| have been brought along by this sort of technology.
|
| In summary, I am much more optimistic that if we had orders
| of magnitude more data, we'd make better decisions, not
| worse. But I agree with your caution that it's not as easy as
| it seems.
|
| [1]: https://www.bmj.com/content/352/bmj.h6080
| captainmuon wrote:
| If you leave the treatment criteria the same, then yes, you
| are absolutely right. But you have to adjust those, too.
|
| Just a made-up example: Let's say someone has an advanced
| test for cancer run, and it comes back positive. You know
| from studies that treating people the same way as before with
| the advanced test leads to worse outcomes because of
| unneccessary treatment etc.. So what you could do is you do
| the simpler test afterwards. If it comes back negative, you
| don't treat -> you are in the same situation as before, only
| you can be more vigilant in future and see if the cancer
| grows. If the simpler test also comes back positive, you do
| the treatment.
|
| It's all about getting data (statistical and otherwise) on
| what the best treatment is, and acting on that.
| iNane9000 wrote:
| As it stands wealthy people can and do find more thorough
| medical treatment, including more frequent and exhaustive
| imaging, labs, etc... The conventional wisdom you cite only
| applies to those who can't seek endless second opinions from
| specialists. There are many conditions that exist and are
| treatable in wealthier societies. The poor suffer those same
| afflictions but are untreated or misdiagnosed.
| soheil wrote:
| I wonder if the equivalent of extreme iatrogenics and
| unnecessary psychological damage and stress also occurs when
| monitoring servers too much. I have a feeling it does. This
| is why I typically set higher thresholds like more disk
| space, memory (equivalent of exercise and healthy diet?) that
| I really need so I stop monitoring my servers religiously.
| [deleted]
| jacquesm wrote:
| Regularly checking people that are otherwise healthy for cancer
| will turn up a lot of cancer through false positives or slowly
| growing ones, will lead to a lot of unnecessary intervention
| and will in fact lead to a reduction in quality of life and
| lifespan. This is one of the reasons why exhaustive cancer
| screening (which was more costly in the past but could have
| been done) was not promoted, it had nothing to do with ability,
| but everything to do with outcomes.
|
| Those cancers where checkups are useful we already do regular
| screenings for.
|
| For aggressive cancers - the ones that are really problematic -
| you would have to do such a test too frequently to make any
| real difference, for instance, if you were to test annually
| you'd be on average 6 months away from your next test, plenty
| of time for such a cancer to develop and kill you.
|
| So this is not the kind of breakthrough that you may think it
| is.
| pieno wrote:
| It seems like you and GP are agreeing on the fact that _right
| now_ we don't do too many preventive checks because the cost
| of testing is higher than the benefits (mainly because false
| positives could lead to risky and invasive follow-up testing
| to confirm that it's indeed a /false/ positive; and knowing
| that you have something sooner rather than later may not
| meaningfully affect the outcome of the disease; and costs of
| tests and trained personnel are huge).
|
| But GP seems to be saying that they hope to see better tests
| _in the future_ , that are not risky or invasive, don't have
| as much false positives, and are less costly to do, so that
| the equation would change and we could actually meaningfully
| improve outcomes by doing large-scale preventive testing.
|
| You would still likely have cases where you cannot /improve/
| outcome by knowing sooner that you have a disease, but as
| long as you are not making matters worse and improving
| chances for a significant subset of people, all while keeping
| costs the same or even decrease costs, this seems like a
| great evolution.
| jacquesm wrote:
| Even 100% true positive rate would not guarantee improved
| patient outcomes with massive testing. This is grounded in
| a poor understanding of what improved patient outcomes are
| all about, which is fine with me but to see this so
| misunderstood is a bit disappointing.
|
| Better tests do not automatically lead to better outcomes.
| They _will_ lead to many more cancers detected, and they
| will lead to more interventions.
|
| Just one example (there are many more): for many tumors the
| risk of the operation to excise it already outweighs the
| risk of the tumor itself leading to damage to the body.
|
| The factors that govern whether an intervention is
| necessary are determined by the rate of growth, the risk of
| meta-stasis, the organ(s) affected, the stage the cancer is
| currently in (and here early detection would at least help
| to get a grip on that) and so on.
|
| But once detected treatment is going to be the norm, and
| that's where the problem lies: treatments are not
| necessarily an improvement over having a mostly dormant
| cancer.
|
| If you were to autopsy all of the cadavers from any given
| country for a period of time you would find a correlation
| with age and the presence of one or more tumors in that
| cadaver, even if the person never had symptoms and died of
| a completely unrelated cause. Treating all of these would
| have resulted in some of those people ending up in the
| morgue a lot earlier and having a reduced quality of life
| both from a medical and a mental health perspective.
|
| Deciding to treat - or not - is not a simple matter.
| petra wrote:
| >> treatments are not necessarily an improvement over
| having a mostly dormant cancer.
|
| This is true today.
|
| But if we could detect cancer at a really early stage,
| relatively reliably, maybe this means we could develop
| new and effective treatments that are low risk and low on
| side-effects ?
|
| And if we had that, early cancer detection will also have
| a totally different meaning, so that could help with the
| mental health aspect too.
| jacquesm wrote:
| We could develop those treatments irrespective of early
| detection, there are plenty of examples of early
| detection of cancers today to make that feasible, this
| does not depend on a new test regime.
| yazaddaruvala wrote:
| You may know more than me about medicine, but when it
| comes to allocating resources, I know just as much if not
| more than you.
|
| If we start to test more, and understand the magnitude of
| the problem better (despite false positives/negatives) we
| can better allocate capital to solving this problem.
|
| Sure, "cancer is horrible, we should already allocate as
| much capital as possible" but this just isn't reality. As
| soon as the addressable market for early-detected cancer
| treatment goes from X per year to 100X per year (and
| 1,000X or 10,000X is "even better"), big pharma has more
| motivation to actually R&D safe treatments for early-
| detected cancers.
|
| Not testing more to detect cancer early is silly, if only
| from the perspective of capital allocation.
| Guillaume86 wrote:
| Your point across this thread is weird because it's not
| the testing itself which is an issue (if we assume the
| testing has a negligible cost economically and is
| comfortable/easy for the subject).
|
| We just need to improve the decision making after getting
| test results (one of these decisions is to decide to not
| do anything), and more data make improving it easier.
| jacquesm wrote:
| But tests do not have a negligible cost, have other costs
| besides the pure monetary value (such as occupying
| valuable lab time that could be spent on symptomatic
| patients instead), are typically not at all comfortable
| and easy because you'll be looking at a biopsy at a
| minimum (which again takes away valuable resources from
| symptomatic patients) and so on.
|
| My argument is not about particular individuals, but
| about populations as a whole and wholesale screening of
| those populations. The consensus is that this does not
| lead to improved patient outcomes _across that
| population_ , though in individual cases it may very well
| be the result.
| [deleted]
| prutschman wrote:
| My lay understanding of the current standard of care is
| very roughly speaking something like:
|
| Patient exhibits symptom => perform a not-especially-
| invasive test Positive test result => invasive test like
| a biopsy Positive biopsy result => heavy-duty
| intervention (although I'm not focusing on this part of
| the chain in what follows)
|
| Both testing and (certain) symptoms have predictive
| value, and don't completely overlap. So there's something
| like this going on:
|
| P(actual problem|no additional information) = really
| really low, which is why they don't scoop out chunks of
| every organ to test "just in case" every time you go to
| the doctor
|
| P(actual problem | [symptom AND positive test result]) =
| generally high enough in at least some cases to justify
| the risk of the biopsy, which is why it's the standard of
| care
|
| P(actual problem | just symptom) = probably not super
| high, which is why the tests are developed
|
| P(actual problem | just a positive test result) =
| substantially lower than P(actual problem | [symptom AND
| positive test result]), so in the general case the
| balance of risk no longer favors the biopsy
|
| In the broadest of strokes, is there anything I've just
| said that you substantially disagree with?
| jacquesm wrote:
| No, there isn't, though it is probably important to point
| out that age, genetic disposition and gender are a big
| factor in selecting what kind of test and if positive
| what kind of treatment - if any - will be administered
| and that this is as you correctly identify on symptomatic
| patients only which raises the base rate in that
| population (the population of symptomatic patients)
| tremendously.
|
| And that's exactly where the issue with indiscriminate
| asymptomatic testing lies, that requires much higher
| quality tests than the ones that can be used in a
| diagnostic setting once a patient is symptomatic.
|
| To add one more unpopular bit of data to all this: there
| is some evidence that the indiscriminate testing for
| certain cancers has gone too far and that it no longer is
| a net positive. But in the presence of certain mutations
| those tests are extremely valuable.
|
| https://www.statnews.com/2018/01/01/cancer-screening-
| misled-...
|
| Biology is messy, and it is quite hard to state up front
| whether or not a test or a treatment - even if in an
| experimental setting it is working - will still be a gain
| if rolled out in a different setting or application.
| Hence all the trials and studies, that's the only way to
| really get a grip on this.
|
| I'm quite curious what the outcome of the large scale
| test the article refers to will be.
| msrenee wrote:
| I'd need to know more about the specific types of cancer
| this screening covers to say anything for sure. However,
| the errors that cause cancerous growth are more common than
| most think and many are not life-threatening. I think
| that's what the other commenter is talking about. The
| intervention for these types of cancer may be more damaging
| than the cancer itself. If these are detected by this test,
| the patient may not understand that intervention is not
| necessarily in their best interest and may have increased
| anxiety or demand treatment when it is not needed.
|
| This is just the first article I ran into.
|
| https://www.sciencealert.com/new-evidence-finds-numerous-
| can...
| bruce343434 wrote:
| Who are "we"? I'm certainly not "regularly" screened.
| jacquesm wrote:
| That's your choice, assuming you live in a developed
| country.
|
| Assuming the United States see here:
|
| https://www.cdc.gov/cancer/dcpc/prevention/screening.htm
|
| and if elsewhere consult your local CDC equivalent.
| postingawayonhn wrote:
| Current screening methods tend to be costly and/or
| uncomfortable for the person being screened. A simple
| blood test could lead to higher uptake and more regular
| screening.
| goodpoint wrote:
| > Regularly checking people that are otherwise healthy for
| cancer will turn up a lot of cancer through false positives
| or slowly growing ones, will lead to a lot of unnecessary
| intervention and will in fact lead to a reduction in quality
| of life and lifespan
|
| This is completely irrational argument. Catching cancers
| early is crucial.
|
| Furthermore, if better information leads to unnecessary
| intervention the blame lands squarely on the hospitals being
| overzealous and greedy.
|
| > For aggressive cancers - the ones that are really
| problematic - you would have to do such a test too frequently
| to make any real difference
|
| Because aggressive cancers go from 0 to dead in a week?
| Please.
| specialist wrote:
| > _will turn up a lot of cancer through false positives_
|
| We will adjust. Examples: breast, cervical, prostate cancer.
|
| Possible scenario: regular assessments every 2 years starting
| at age 18. Establishes your personal baseline. When something
| changes, you'll know.
|
| It's better to know than not know.
| toomuchtodo wrote:
| Next steps are mRNA vaccines and gene therapy for the
| cancers this detects. You can't manage what you don't
| measure.
| tarsinge wrote:
| > Those cancers where checkups are useful we already do
| regular screenings for.
|
| More like "are <practical given available tests> and useful".
|
| Regarding your last paragraph cancer screening seems very
| rare except for one or two types (at least where I live), so
| statistically yes an annual test will miss the worst case you
| presented, but for the vast majority it will be a huge
| improvement.
| jacquesm wrote:
| For those cancers where it makes sense, yes. But typically
| screening is voluntary (as it should be), and there are for
| some cancers strong genetic indicators that a person is
| susceptible to a particular kind of cancer, which
| immediately changes the equation for that particular person
| tremendously in favor of screening.
| 11thEarlOfMar wrote:
| I see it more in the vein of vaccinations. A preventive care
| activity, not as a reaction to a symptom. Speaking only for
| myself, I am regularly screened, asymptomatically, for skin,
| prostate and colon cancers. That screening is a non-event for
| me because I grew up knowing that we will get screened on a
| regular basis for these cancers.
|
| With additional asymptomatic testing, there will be false
| positives. Re-test using a specific test and if still
| positive, a biopsy. How frequently do false positives lead to
| unnecessary procedures with the current asymptomatic
| screening?
|
| What would the rate of unnecessary intervention be, vs the
| rate of lives saved through early detection?
| jacquesm wrote:
| With the present invasive methods of excising cancer the
| answer is that on an individual basis you might be better
| off with early detection but on a statistical basis across
| a larger population you'll be worse off. The important
| variables are patient age, how aggressive the cancer is
| (growth rate), what the risks of that particular type of
| cancer metastasizing are, what your genetic disposition is
| etc.
| 11thEarlOfMar wrote:
| Again, personally, I lost both parents to cancer. One
| thyroid (very slow progression) one pancreatic (very
| fast). In both cases, I believe that pre-symptomatic
| detection would have had a high probability of
| eradicating their cancers. That experience skews my view
| and if I get the opportunity, I'll have these tests done
| 3x annually.
|
| But I understand your point. How about making it
| elective? That way, people who prefer to not endure the
| risk of false positives or the anxiety of awaiting the
| test results can opt out.
| jacquesm wrote:
| I'm really sorry for your loss, but please try to keep a
| healthy balance between personal tragedy versus medical
| policy set for a whole population, which are two entirely
| different things.
|
| For any particular individual, _especially_ those who end
| up dying from cancer early detection would have likely
| mattered. Which is exactly where the problem lies: that
| is a large number of people, but still (much) smaller
| than the number of people who will end up with positive
| cancer test. And policy is set by the outcome for the
| population as a whole, not for any particular individual.
|
| In most places in the developed world cancer screening is
| already elective, but not for all types of cancer. Even
| so, how often are you going to do it? Once every year
| could easily be too slow to make a difference, and these
| tests aren't free so say a bi-annual test on _all_ of the
| population would wreck the ability of the medical world
| to do much else. This is a tough problem to solve,
| especially because wetware tends to be finicky to work on
| and tiny little details will have a huge effect on
| outcome.
| BallyBrain wrote:
| Does anyone know which tests are availabe today excluding
| CT scans. For men (which is relevant to me) I know of:
|
| Prostate, Skin, Colon
| ggrrhh_ta wrote:
| Have heard your argument on the false positives and
| unnecessary interventions many times.
|
| It is not a good argument. In fact, it makes no sense. If you
| get a positive with an uncertainty in its accuracy, at the
| very least, the test is repeated. But even more, you can use
| the information from the investigation of the reason for the
| false positive to improve the tests in the first place. If we
| weren't humans and the uncertainty of the test is known then
| at the very very very least you could throw a dice to decide
| whether you discard or not the test result.
|
| If more information leads to worse decisions it just means
| that the noise level introduced by the test is just too high.
| A way to reduce the noise is two amplify the signal, and a
| way to amplify the signal is to look for more information
| (other tests, other indirect measurements: i.e., look for B
| if A was positive, etc.).
| fabian2k wrote:
| This is a very well known problem for many kinds of
| screenings, and the solution is not as simple as you claim.
|
| You can't just repeat the test, that is generally not where
| the problem lies. You'll get a second positive result and
| still don't know if it's a false positive or not.
|
| And in many cases there aren't other non-invasive test you
| can perform. If you can't actually determine reliably if
| some anomaly will cause trouble before removing it, whole
| population screening will cause unnecessary operations.
| [deleted]
| ggrrhh_ta wrote:
| BTW... years ago I was rather supportive (albeit not having
| voiced it) of the argument that false positives lead to
| unnecessary interventions and thus screening should be
| itself gated.
| jacquesm wrote:
| Your understanding as evinced by the comment above leaves
| me to wonder if you actually get that this is not about
| individual outcomes but about the overall statistics.
| Even if more accurate tests would turn up more true
| positives that _still_ would not necessarily result in
| increased patient outcomes. That is why absent symptoms
| testing makes sense for only a very low number of cancers
| where early detection does improve patient outcomes
| significantly, typically this is vastly improved if there
| is knowledge about the genetical make-up of the
| individuals.
| nybble41 wrote:
| > absent symptoms
|
| A positive blood test _is_ a symptom. One which you 'll
| miss if you don't do the blood test regularly.
|
| And looking for symptoms (other than a blood test) is a
| form of testing... one with much worse accuracy (both
| positive _and_ negative) than the blood test, especially
| in the early stages.
| jacquesm wrote:
| Just so we are using the same definitions for the words
| we write, here is the definition of 'symptom' in a
| medical context:
|
| https://www.cancer.gov/publications/dictionaries/cancer-
| term...
|
| "A physical or mental problem that a person experiences
| that may indicate a disease or condition. Symptoms cannot
| be seen and do not show up on medical tests. Some
| examples of symptoms are headache, fatigue, nausea, and
| pain."
| jacquesm wrote:
| Your belief has no representation in medical science, which
| is mostly evidence based. A lot of data has been collected
| on this, studies (many) have been conducted and the general
| consensus is that more testing absent symptoms does not
| lead to improved patient outcomes.
|
| That you want to have some kind of theoretical argument in
| the face of this evidence might be interesting to you but
| it isn't to me.
| mbesto wrote:
| > A lot of data has been collected on this, studies
| (many) have been conducted and the general consensus is
| that more testing absent symptoms does not lead to
| improved patient outcomes.
|
| Where can I find the studies that conclude this?
| jacquesm wrote:
| https://www.ncbi.nlm.nih.gov/books/NBK66205/
|
| https://www.ncbi.nlm.nih.gov/books/NBK223933/
|
| https://www.theguardian.com/society/2021/may/12/annual-
| scree...
|
| Those are popular and accessible, the actual studies you
| can find through Google Scholar, SciHub or various
| medical publications.
|
| This is not something where the general public - or
| software developers, who seem to treat cancer as a bug
| that needs to be fixed - are going to be very helpful, I
| am more than happy to trust the medical establishment
| with this.
|
| What _would_ be a game changer would be rather than
| improved testing something that would destroy tumors in-
| situ in a non-invasive manner that does not involve
| radiation or attempts to poison the body just this side
| of death.
| amluto wrote:
| You're making an unwarranted assumption: that the choice
| is between early detection _with current responses to
| detected cancers_ and no early detection at all.
| Optimizing the response to an early detection will give a
| result no worse than either of those, since the choices
| of what to do include doing whatever doctors did in the
| studies that have poor results as well as doing nothing
| at all.
| jacquesm wrote:
| No, that is not the assumption. The assumption is that
| the only way in which such a test will be useful is by
| applying it absent symptoms to the population en-masse
| aka screening.
|
| And that - no matter who good the test, and no matter how
| early - leads to a decrease in positive patient outcomes.
|
| This is established medical science, and it pains me to
| have to continue to point out the same thing over and
| over again, but since I started with this response I feel
| obliged to continue to do so.
|
| The outcome of a cancer treatment is not pre-determined,
| there are a lot of individual factors at play here that
| will have a huge effect on the outcome, possibly much
| larger than the effect of that particular cancer itself.
|
| So en-masse screening leading to an increased number of
| treatments of pre-symptomatic cancers with those current
| responses is not a choice, we _know_ that this will lead
| to a worse outcome across a population.
|
| Early detection does not add anything to that. If you
| could pick out those individuals for which early
| detection would make a difference then _that_ would be a
| gamechanger, and here the ball is currently in the
| genetics court.
|
| The other part where major change can be made is by
| finding ways to treat cancers in a way that is non-
| invasive and does not put the patient further at risk (so
| no surgery, chemotherapy or radiation therapy).
| Silhouette wrote:
| _And that - no matter who good the test, and no matter
| how early - leads to a decrease in positive patient
| outcomes._
|
| You keep writing comments in absolute terms and talking
| about evidence, but how do you reconcile your position
| with the results of successful screening programmes like
| cervical smear testing? Detecting and treating high risk
| HPV before it causes changes that can turn into cervical
| cancer has dramatically reduced the harm caused by
| cervical cancer itself at a population level. Routine
| screening of this type isn't normally recommended for
| young women, but it becomes increasingly effective with
| age and screening programmes operate accordingly.
| jacquesm wrote:
| Yes, but that's one specific cancer. There are a few
| others for which this is the case and absent genetic data
| a few that are borderline cases (notably: breast cancer,
| where the presence or absence of a mutation is a very
| relevant bit of data).
| Silhouette wrote:
| So you do agree that evidence-based screening programmes
| can be effective then? In that case, I'm sorry but I
| don't quite understand the point you're trying to make
| here.
| jacquesm wrote:
| Yes, they can, but not in a blanket fashion where a test
| with a relatively high false positive rate and a
| relatively low sensitivity (between 18 and 50% for this
| particular test) is released without patient outcomes as
| the main driver of whether or not to apply the test
| absent further symptoms.
|
| Whether this test is one that can serve in that
| particular role is definitely not something that has
| already been determined and those advocating for such are
| ignoring a mountain of established science and are simply
| jumping the gun.
|
| Policy is set by the overall effect of application, which
| can be quite different than applying that same tool in an
| individual setting. This whole thread started with
|
| "This is one of those medical revolutions that I am
| waiting dearly for.
|
| Facilities that are not hospitals(to avoid the risk of
| occupying medical devices that sick people need) built to
| _regulary_ check up otherwise healthy people for
| preventive care."
|
| And that is not something you do without taking into
| account the downsides. Whether this is revolutionary or
| not remains to be seen, it definitely is a useful test
| based on what I've read about it so far.
| Silhouette wrote:
| Well, yes, it's only worth running a screening programme
| if you have a usefully accurate test and if you can then
| make some useful intervention after a positive result. Is
| anyone here disagreeing with that, though?
|
| Maybe we interpreted OP's comment that you quoted
| differently? I read it as being in favour of preventative
| medicine as a whole, not necessarily endorsing this
| specific test at this specific point in time.
|
| Maybe I'm also interpreting some of the other comments in
| this discussion, including yours, differently to how
| their authors intended them. My concern is that as
| written they appear to be criticising all use of
| screening, regardless of its efficacy, which is extremely
| dangerous.
| jacquesm wrote:
| That certainly isn't the goal, it is strictly meant
| within the context as established by the root comment. To
| present this at the present time as a revolutionary
| breakthrough and to suggest using this test in particular
| for mass screening is not a path that will lead to a good
| outcome unless a lot more data is gathered to support
| that position.
|
| The people that have built this are at the forefront of
| this field, I've been following them for quite a while -
| since the announcement in March last year - it has direct
| bearing on some other things that I'm involved with and
| I'm hopeful that it will at first be a useful diagnostic
| tool and that in a later stage - after the kinks have
| been worked out and there is sufficient data - that it
| might help with more than that.
|
| Preventative medicine obviously has its place and for
| selected cancers we are now in a phase where early
| detection leads to improved outcomes. But we should
| continue to be weary of overselling this - the same has
| already happened with other cancer tests.
|
| Absent symptoms mass testing has serious risks and these
| will obviously be taken into account when setting policy,
| the article is actually reasonably neutral in this
| respect so I wonder why it leads to an immediate response
| that is equating this with a medical revolution. It may
| well be, but there is no evidence right now that this is
| the case.
| ggrrhh_ta wrote:
| Well. With a bad test, what is necessary is to improve
| the test. The argument "outcomes are worse off with more
| absent symptoms testing" is really saying that symptoms
| is more predictive than the test itself: test is positive
| if [symptoms & positive result] test is positive or
| neutral if [no symptoms & should have been screened &
| positive result] and test is negative if [no symptoms &
| should not have been screened & positive result] (notice
| that this does not change the outcome to not testing
| people without symptoms and without another reason to do
| so). Until the tests/decision protocols were improved to
| avoid false positive, this third case should be
| communicated to the person as a negative result of the
| test (if we are convinced that the overall outcome is
| better off if the test should not have been administered
| at all), but I would find that unethical and dehumanizing
| and I understand touches on lots of ethical issues: the
| stress of waiting for a result, the liability of not
| being an actual false positive, etc. So, I understand,
| that given the current state of the testing, the decision
| is to restrict when to do it.
| jacquesm wrote:
| You are visibly making progress in your understanding of
| the problem, for which you are to be commended,
| especially if you are a complete layperson in this field.
| Thank you.
|
| This test isn't a 'bad test', though applying it in the
| wrong way can lead to bad outcomes. This is why tests
| used absent symptoms have to have a false positive rate
| that is much lower than the base rate at which the
| disease occurs. These tests - unlike software tests -
| should not be thought about in absolute terms but in
| terms of probability, so a positive test indicates a
| probability that you have a specific disease, but it is
| very well possible that you do not have it, and a
| negative test indicates a probability that you do not
| have it - but it is very well possible that you in fact
| _do_ have the disease. And the reasons for a false
| positive or false negative may have nothing to do with
| the test itself, but could easily be an environmental
| factor or some benign aspect of the test subject that was
| not accounted for when designing the test.
|
| Whether or not a test is suitable for mass screening
| hinges on the factors above, the base rate for the
| disease, the age of the group being tested, in some cases
| gender and so on. In order to have a positive outcome
| across the population all these factors have to be taken
| into account and by the time that you have done so there
| are - unfortunately - at the moment no miracles to be
| had. But combinations of knowledge, for instance a
| genetic pre-disposition to a certain disease + a positive
| test can have much higher signal to noise ratios than
| either by themselves.
|
| But make no mistake: this is an important development in
| medical diagnostics and it may very well be that once
| more evidence has been collected and some of the kinks
| have been worked out that this particular test or an
| improved version of it can be applied in a screening
| setting for one or more of the cancers that we currently
| have no reliable detection method for and that _could_ be
| cured if detected early enough given a high enough base
| rate and a low enough false positive rate.
|
| Note that the scientists behind the project are very
| careful with their statements and that the reporting on
| this was actually quite neutral and trends to cautious
| optimism, which I think is warranted, but until the
| result of the new studies is known it is way too early to
| shout 'revolution'.
| melling wrote:
| Less information is better?
|
| That would be a bit of a paradox in science. I suppose we
| might take 2 steps forward and 1 step backward in the
| short term. As medical science advances, hopefully we can
| address any shortcomings from the additional early
| knowledge.
|
| I noticed that pancreatic is on the list. This cancer is
| almost always fatal because we can't detect it early.
| colinmhayes wrote:
| People are idiots that don't understand statistics.
| Telling them they tested positive is all they hear, and
| it leads to them making subpar decisions that often
| involve invasive surgery. Yes, it's paternalistic, but
| the fact is most people aren't informed enough to make
| medical decisions for themselves.
| jacquesm wrote:
| No, that's not the point. On an individual basis knowing
| for sure that a person who has symptoms has cancer,
| especially what kind of cancer, is a positive. On a
| population scale knowing that people without symptoms may
| have cancer with an 0.5% false positive rate and an
| 18-50% true positive rate is quite possibly a negative.
| Fomite wrote:
| Less information can be better. Or more accurately,
| conditional probabilities can be better than
| unconditional probabilities.
|
| For example, a _large_ number of unnecessary antibiotic
| treatments, which fuel resistance, are triggered by doing
| diagnostic testing on patients with no symptoms.
|
| "Diagnostic stewardship" is a concept that exists for a
| reason.
| cortesoft wrote:
| > Less information is better?
|
| This really depends. Information that does not help make
| a good decision is just noise. It might seem like
| diagnostic information should always help make a good
| decision, but that isn't always the case. If the false
| positive rate is higher than the base rate, a positive
| test would be more likely to be wrong than right, even
| with a very high accuracy.
|
| https://en.wikipedia.org/wiki/Base_rate_fallacy
| sweetdreamerit wrote:
| Your point is interesting. Can you cite some literature
| that supports it?
| jacquesm wrote:
| See below, there are quite literally 100's of studies
| supporting this so it should not be difficult to find
| many more articles about this.
| TaupeRanger wrote:
| Look up the term "iatrogenics" or check out oncologist
| Vinay Prasad's podcast called Plenary Session where he
| often talks about the dangers of over screening.
| dmitryminkovsky wrote:
| Not just that, but neither GP nor anyone else in this
| thread seems to be mentioning the mental health
| implications of constantly screening for life threatening
| diseases. For me, and many others I am sure, this would
| be _bad_. My quality of life would suffer tremendously,
| to the point of likely substantial loss of mental
| function. And I am definitely _not_ one of these "we all
| die someday" types. Far from it. It's just that if you're
| prone to anxiety, especially the hypochondriasis variety,
| the picture is much more complex than thinking of
| yourself as a server hooked up to monitoring.
| jacquesm wrote:
| Yes, that's a very important point. Even regular checks
| for cervical cancer or breast cancer can be a huge stress
| factor, especially in the period just prior to the test
| and in the waiting period until the results are in, and
| even more so if the test yields a false positive.
| mrtnmcc wrote:
| Is the problem not so much the testing, but that most
| current treatments for cancers are so crude? If you have
| a relatively asymptomatic cancer, the treatments (chemo,
| surgery, proton beams) and psychological stress of
| discovery could be worse (statistically) than letting the
| body naturally take care of it. This probably depends
| very much on the cancer ( e.g., some Thyroid cancers
| might be better left alone).
|
| If our best treatment for fixing a harddrive was to hit
| it with a hammer, then maybe we'd also conclude
| monitoring for minor bit errors in data centers is unwise
| too.
| jacquesm wrote:
| Fair point: if we had a completely non-invasive cancer
| treatment then that would be a game changer (I made that
| some point in an earlier comment far down in the thread).
| And in that case it would lead to improved patient
| outcomes. But the current regime of tests+treatment
| options does not in the general case - and there are
| quite a few exceptions that mostly have to do with
| genetics - lead to improved outcomes.
| goodpoint wrote:
| > mental health implications of constantly screening for
| life threatening diseases
|
| ...to be contrasted with the mental health implication of
| living with the knowledge that you are *not* being tested
| and that cancer can grow undetected for years.
|
| That, if anything, is a very good reason for anxiety.
| bijant wrote:
| You're correct in that this is a prevailing view in
| epidemiological/Public Health circles. But Medical
| Science is not only the macro but also the micro level
| perspective. Individual Practitioners of medicine might
| well appreciate more and earlier Data. A first principals
| based argument is a complementary approach that might
| uncover things that an empirical view might hide.A good
| example of this is the Australian Noble Laureate Barry
| Marshall (https://www.discovermagazine.com/health/the-
| doctor-who-drank...). As long as the hypothesis can
| consequently be validated in controlled clinical studies,
| a theoretical argument even without existing foundation
| in empirical literature can still make for good science.
| jacquesm wrote:
| Absolutely, on an individual basis is where the
| difference can be made and this is exactly why it is
| important _if_ you are tested positive for some cancer to
| work together with your oncologist to ensure the best
| possible outcome for you. The interesting thing here is
| that laypeople tend to be in favor of massive testing and
| almost always want to be operated on /have
| chemotherapy/have radiation therapy even if that is not
| necessarily the best path for them.
|
| This leads to lots of suffering and hardship.
| dxyms wrote:
| > _If you get a positive with an uncertainty in its
| accuracy, at the very least, the test is repeated. But even
| more, you can use the information from the investigation of
| the reason for the false positive to improve the tests in
| the first place._
|
| This assumes that the false positive is caused randomly.
| That's not the case. False positive tests are usually
| followed by false positive tests. Then it will take years
| to find out if it was a false positive or not.
| ggrrhh_ta wrote:
| That is very interesting. I assumed that false positives
| is generally a testing error (testing with another method
| or from another company would not lead to the same
| result). If the false positive is a result of a non-
| dangerous anomaly of the person being tested, then, I see
| how testing without symptoms can be worse.
| jghn wrote:
| Herein lies the real issue. Biology is a very, very messy
| science. So yes it could just be a testing error. But it
| might not be. It might be that something in your body
| behaves in a way that's unexpected. It might be some
| other non-dangerous anomaly as you cite.
|
| We understand far more than we did say 20 years ago. But
| the problems are non-trivial on a scale most people don't
| appreciate.
| anonymouse008 wrote:
| > will lead to a lot of unnecessary intervention and will in
| fact lead to a reduction in quality of life and lifespan
|
| That's a wild assumption that every cancer will be acted upon
| in the same manner as a stage IV even in the nascent state...
|
| Given the quality of healthcare and the desire to not be sued
| for malpractice, it's a fair concern.
| ssijak wrote:
| The test in the article actually has very few false
| positives. And who knows, maybe even those false positives
| were just extremely early cases of cancer.
| jacquesm wrote:
| Very few false positives: 0.5% false positive rate times
| 1,000,000 people screened translates into 5,000 false
| positives, which is in absolute terms not a small number.
| Those will take away resources from symptomatic patients.
| TheHypnotist wrote:
| Slowly growing cancer still sounds bad enough to get some of
| that "unnecessary" intervention. I'm no doctor, but my
| understanding is that the aggressive cancers typically get
| discovered due to a symptom of sorts and thereabout is your 6
| month countdown. Again, from a layman's perspective and
| understanding, those cancers need to start somewhere. What's
| the harm in catching them as early as possible? If a blood
| test leads to a scan and the scan turns up negative, what's
| the issue?
| jacquesm wrote:
| Depends on your age, genetic disposition and many other
| factors besides. Once you have symptoms your oncologist
| would be the only person qualified to determine what for
| you in particular is the best course forward.
|
| In some cases that 6 months might be very generous, in
| other cases you are better off to do nothing (especially if
| you are advanced in age and the cancer is growing slowly).
| It all depends.
| mrfusion wrote:
| My car's check engine light came on and a costly mechanic
| visit didn't find any problems so we decided to remove the
| check engine light.
| jacquesm wrote:
| That's not an appropriate analogy for more reasons than I
| care to relate here. Suffice to say that if you believe
| that the engine check light is the equivalent to a positive
| cancer test that you probably should stay out of medicine
| ;)
|
| And maybe out of your garage as well...
| a_conservative wrote:
| Why are you responding to random commenters on HN as if
| they are the ones getting ready to go out and start
| writing the official policy of a country?
|
| Discussion is good. It's ok for people to be wrong and
| disagree. I'm not even saying they are wrong, but if they
| were- do you really need to go around telling everyone
| that some opinion that crossed their mind over a cup of
| morning coffee would be a disaster if implemented as
| national policy?
| iandanforth wrote:
| I detest this mindset. It is incredibly counter productive.
|
| "Our tests are bad, so lets not test" is _not_ a thought
| worthy of respect. This states that you know about a problem
| but want to continue to ignore that problem. Reprehensible.
|
| No, we should take the exact opposite approach. Test everyone
| constantly until such methods become both cheap and powerful.
| So yeah we all have some cancer load but if the diagnostic or
| treatment systems can't deal with that reality then those
| systems need to change.
| jacquesm wrote:
| The problem is not my mindset, but your understanding of
| the subject material. Patient outcomes have very little to
| do with the quality of the tests, even a 100% accurate test
| would not necessarily lead to improved patient outcomes
| because these are defined independent of the tests.
|
| You are treating this like a software problem, but it
| isn't, it's a medical problem, and medical problems tend to
| be complex because they have a ton of confounding variables
| that make it hard to have a one-size-fits-all method for
| dealing with medical issues.
|
| What needs to change is that people need to realize that
| they have a field of expertise and that the medical domain
| has its own experts who typically dedicate a lifetime to
| their profession, their general consensus is that improved
| tests are welcome but in and of themselves are not enough
| to guarantee improved patient outcomes. Yes, this is
| unfortunate, but it is also a simple reality, you can
| either accept that or not, that's up to you but if you want
| to make a change there than you probably should join the
| medical profession. Most likely by the time that you have
| completed the requirements you will have shifted your
| viewpoint away from the software domain's mindset that all
| bugs can be found and squashed by the next sprint. Which by
| the way judging by the general quality of software out
| there is also something that doesn't work out in practice
| as we believe it should in theory.
| iandanforth wrote:
| You don't know what you're talking about.
|
| Before my software career I spent a few years working in
| a diagnostic medical field. Specifically osteoporosis
| testing. I worked both in a research capacity at Stanford
| looking at osteoporosis in older men (not pretending to
| be the PI here) and in a day to day testing clinic. So
| I've seen exactly what happens when you test a cross-
| sectional asymptomatic sample of the populous and what
| happens during the normal course of referred testing.
|
| Low bone mass at the spine, hip, heel, and forearm as
| measured by DXA are correlated with increased risk of
| fracture, but it's only a correlation. Some people have
| resilient architecture which looks porous on an x-ray but
| only leads to serious fracture _much_ later in life.
|
| Because the current diagnostic tests are set up with
| levels like 'osteopenia' and 'osteoporosis' the reaction
| to clinical referrals was most often treatment. Some of
| those treatments have serious side effects like
| necrotizing impacts on the jaw. However the reaction to
| testing in a large asymptomatic population was much more
| likely to be an increase in preventative behavior
| (exercise) or no treatment except in extreme cases. While
| our study was exploratory and didn't have a treatment
| cohort (we cared about the impact of sleep quality on
| bone mass) we got to see _a lot_ of older men who if they
| were referred to a clinic might have received treatment
| _because that 's what clinics do_. Instead we had
| sufficient data to discuss what's normal and what isn't.
| For a time we were the leading experts in the world on
| what "normal" meant.
|
| Because I've conducted these tests myself and seen data
| from hundreds of experimental and clinical patients I
| feel comfortable contrasting the two. The problem is the
| clinical medical field reacting to a lack of data with
| over-prescription of treatments.
| jacquesm wrote:
| Sure, but that's a completely different setting than the
| one the OP described: mass testing for presence of
| cancers by non-specialist labs. And that's the thing that
| triggered my response. The outcome of such an approach
| could easily be a negative one.
|
| FWIW I too have some experience with medical diagnostic
| systems (specifically: cancer testing), and one of the
| main reasons why I'm still skeptical about this test is
| that for many cancer types tested for the base rate is
| much lower than the false positive rate.
| plank_time wrote:
| This is an absolutely absurd thing to say.
|
| "We've never had blood tests that detect pancreatic
| cancer early, therefore we should never use them because
| when we used other means to try to detect early, it
| didn't lead to better outcomes."
|
| If you can detect colon, kidney pancreatic or liver
| cancer early, you might be able to do surgery or develop
| treatments at the stage 1 stage. Right now we don't have
| anything except MRIs and CT scans that are too hard and
| expensive to do frequently. And if you are diagnose with
| pancreatic cancer it's usually so late that you will
| basically die in weeks.
|
| You're basically saying "give up. Even if we detect early
| you all die anyway" which is frankly stupid. You're
| discounting the possibility that early detection by means
| of a blood test adds whole new layers of possibilities to
| fight those particularly dangerous cancers.
| jacquesm wrote:
| But: that surgery is not without risk, and if there are
| no symptoms there is a fair chance that there _never_
| will be symptoms. Depending on your age and your genetic
| make-up you might be more or less at risk. There is such
| a thing as spontaneous remission and so on.
|
| So no, I'm not 'basically giving up', and no you won't
| die anyway (well, unless you take that in the most
| abstract way), in particular likely not from cancer.
|
| Even for those cancers where we do screen (such as for
| instance breast cancer) it is not a given that the
| increased frequency of detection has led to better
| patient outcomes.
|
| But once you know someone's genetic disposition increased
| frequency of testing might be advantageous.
| BallyBrain wrote:
| I don't see why early detection means early treatment.
| What if after detected, the illness is monitored instead.
| If it then gets to a point where the treatment is no
| longer considered risky for the stage of the illness,
| then the treatment can proceed.
|
| It would also give the person the opportunity to change
| lifestyle to perhaps prolong the time that the illness
| will become a problem, or perhaps halt its progress
| altogether.
|
| Additionally, the person who is aware of such illness,
| can keep an eye out for symptoms related to it, that
| might otherwise be ignored as something else. At which
| point normal cancer treatment can progress.
| jacquesm wrote:
| This is a tricky bit. There is a lot of interplay here
| between medical professionals and the general public, and
| not all of that is either rational or ethical. But absent
| symptoms non-treatment is better than treatment.
|
| Data about unnecessary procedures is relatively
| plentiful, which is of course sad, whether that's driven
| by commercial incentives or the need for 'something to be
| done' is not something that I have any grip on but it
| certainly is problematic.
| BallyBrain wrote:
| Sounds to me like the issues with this early detection is
| more of a regulation and education problem then. That
| could be fixed.
| plank_time wrote:
| Again, absolutely absurd. Many cancers have no symptoms
| until it's too late. Do you even understand this? At that
| point the choices for treatment are extremely limited.
|
| Even breast cancer needs x-rays to detect lumps, not
| detect cancer. You need a subsequent biopsy to
| differentiate. That's our technology right now. If we had
| a blood test to detect cancer, not lumps, it's game
| changing.
|
| Maybe after a generation of early detection, new outcomes
| will emerge if we can detect the most deadly cancers
| early. You're taking old studies and applying them to new
| technologies and saying "it won't work." It's ridiculous
| that you are doing this.
| jacquesm wrote:
| Even if you detect cancer you will _still_ need a biopsy
| to figure out which bits are the cancer and which bits
| are just 'lumps'.
|
| Yes, it is a game changer, but it is not the kind of game
| changer that this is being made out to be here and mass
| screening using this method is not going to lead to
| improved outcomes.
|
| As an extra tool in the toolbox of the diagnostician it
| is very useful.
| plank_time wrote:
| It's pretty easy. If blood test says "liver cancer
| positive. Colon cancer negative." you check the liver for
| cancer. No need to check the colon for cancer. No need to
| scan the entire body for lumps.
| graeme wrote:
| Not that easy. "Check the liver for cancer" has lots of
| risks: surgery and the resulting tissue injury.
|
| I'm generally inclined towards the position of more
| testing....but there are very real tradeoffs to any of
| the interventions that a blood test could prompt.
| jghn wrote:
| Also, you might have identified liver cancer that came
| from the patient's kidney. Or a colorectal cancer that
| came from the patient's liver.
| colinmhayes wrote:
| What happens when it turns out that most of the people
| having surgery don't have cancer? Because that's the
| reality of tests with a .5% false positive rate if less
| than 1% of the population is positive.
| [deleted]
| goodpoint wrote:
| > surgery is not without risk, and if there are no
| symptoms there is a fair chance that there never will be
| symptoms
|
| Another incredibly irrational argument.
|
| If the risk from surgery outweighs the risk from cancer
| it it should not be performed.
| wrcwill wrote:
| this just reads to me as "our tests don't test for the
| right things, since when we act on those tests (even if
| they were 100% accurate), it doesn't lead to better
| patient outcomes".
|
| I feel like a better conclusion is that we need better
| tests, that detect things that when acted upon improve
| patient outcome. Of course, we're nowhere near that yet,
| but do you really think in 1000 years we will still wait
| for patients to be responsible for correctly noticing
| symptoms and going to the doctor? Of course not.
|
| It's good that we have studies that show we should move
| with caution in this territory, but completely ignoring
| it forever seems absurd.
| laputan_machine wrote:
| For someone who has no medical background, you are
| certainly spouting a lot of nonsense as if it was fact.
|
| The WHO, for example, disagree.
|
| https://www.who.int/activities/promoting-cancer-early-
| diagno...
| jacquesm wrote:
| The fact that you link to that and apparently do not
| understand it combined with a personal attack is enough
| to disregard your comment for me.
|
| But let me stress this in case it wasn't clear to you:
| screening and early diagnosis are not the same thing.
|
| If you screen a large population for cancer you will turn
| up a lot of cancers that may never become a problem, or
| that may even end up being re-absorbed without the need
| for intervention, as well as a large number of false
| positives.
|
| Early diagnosis means that there are already symptoms.
|
| Please don't confuse the two.
| laputan_machine wrote:
| You come in and flame other users, but then take deep
| offense when you get it back. Treat others with respect
| and in turn you'll receive it.
| pessimizer wrote:
| Disagreement is not "flaming." Jacquesm has been
| generally respectful and factual. The closest they have
| come to rudeness is when people refer to "facts" not in
| evidence or link to things that they haven't read or
| understood well, and even that impatience was
| explanatory.
|
| This comment is simply a personal attack.
| laputan_machine wrote:
| I am sorry if you cannot understand what I am talking
| about, that you are clearly misunderstanding what I am
| saying.
|
| I will write in this deeply arrogant fashion and refuse
| to link to anything I'm talking about, and when
| questioned I will infer that the people I'm replying to
| are utterly moronic (without saying quite such, I will
| instead say things like 'I'm sorry you don't understand /
| let me make this clear / you shouldn't be posting things
| you don't understand').
|
| I will continue to write as if my stance is absolutely
| correct even though I am not an expert in this field, I
| will write as if I am.
|
| And then when people call me out for my arrogance I will
| insist I've done nothing wrong and will be confused.
|
| Baffling.
| a_conservative wrote:
| > The problem is not my mindset, but your understanding
| of the subject material.
|
| IMO, that is inflammatory and arrogant.
|
| More broadly speaking, much of the arguments in this post
| seem almost political. They are dressed up in fancy
| language, but essentially boil down to "We can't give
| these peons information that they aren't smart enough to
| deal with"
|
| That is an extremely arrogant position to take, even
| though I do believe there is some truth that knowledge
| can be counter-productive.
|
| Who gets to be the gate-keeper?
| jacquesm wrote:
| I think I've spent more than enough time in this thread
| going out of my way to explain things in as clear and
| simple a manner as I know how to and if have offended
| anybody then I apologize for that, it certainly wasn't my
| intention.
| dekhn wrote:
| I think you should stop trying to derate people who you
| think know less than you. It's very unattractive. Be
| aware there are folks with extensive public health
| experience (that would be me) watching you insist you're
| right. While I totally appreciate what you're trying to
| do (help software engineers understand why medicine is
| complex), please do understand that GRAIL is tightly
| integrated with the PH community, did their work from a
| good-faith perspective, and came up with a product that
| does "do" something. Now it's up to the medical community
| to evaluate whether it truly provides something that
| doesn't just end up costing us more money and not helping
| people.
| jacquesm wrote:
| That's perfectly accurate: the problem is that people
| tend to run with things like this as though they are the
| miracle that everybody has been waiting for and that is
| not the case, it is a very important development but in
| the right hands and not as a tool that will lead to - yet
| another - round of disappointment in the 'war on cancer'.
| The whole thread has devolved into people arguing from
| hope rather than from facts. This set of tests is a very
| useful thing to have. But the 50% true positive rate, 18%
| true positive rate for stage I cancers and the false
| positive rate combined make it at present - as far as I
| understand this - a tool that could when used as a mass
| screening tool easily do more harm than good.
|
| I'm more than willing to be convinced otherwise but with
| relevant data. FWIW I've been following this particular
| development closely because it has direct implications
| for a start-up that I have had a lot of contact with that
| is also in the early detection space and they were
| adamant that the combination of factors is such - and so
| complex - that test accuracy is trumped significantly by
| absence of symptoms in otherwise healthy patients.
|
| Your input on this would be greatly appreciated.
| dekhn wrote:
| my input is that I've been involved with GRAIL since the
| beginning and I think they've actually done something. We
| don't have the data to say one way or the other.
|
| I am not arguing with most of your points, it's just that
| you're not being epistemically humble. I find it's far
| better to just act humble even when you aare schooling
| people who persist on believing in magic.
| jacquesm wrote:
| Fair enough.
|
| I sincerely hope that this test will drive down the cost
| of testing and that they will get the kinks ironed out, I
| think it is a major development and I'm actually afraid
| that those that oversell it will cause it to end up being
| tainted, as has happened with many other cancer related
| diagnostics and potential treatments. Cancer seems to
| bring out an emotional response rather than a rational
| one, typically because almost all of us have direct
| knowledge of one or more people in our environment that
| succumbed to it.
|
| A lot of work has been done since this development was
| first announced and there are still quite a few kinks
| that will need to be ironed out. The whole idea - such as
| promoted in this thread by some - that this makes cancer
| a matter of 'simply looking at the right organ' is so
| laughably oversimplifying reality that some balance is
| required, and I think at some point my irritation got the
| better of me.
|
| So thank you for pointing that out.
|
| And to add to that: It _definitely_ is not my intention
| to suggest that this test is without value.
| elbasti wrote:
| This is not a question of mindset, it's a question of
| statistics when you're trying to identify anything that is
| rare.
|
| Take prostate cancer as an example. It's a relatively
| common cancer, with an incidence of .1% [0].
|
| If you have an _incredible_ screening test with a 99%
| specificity (ie, 1% false positive rate), then:
|
| If you test 100,000 people, you will correctly identify 100
| people with cancer, and misdiagnose one _thousand_ people
| as false positives.
|
| There are consequences to having a false positive:
| unnecessary interventions, surgery "just to be safe",
| stress, etc.
|
| This is why you limit testing to populations that have a
| higher probability of being ill (namely, show some sort of
| symptom).
|
| Now imagine being tested for 100 things: the odds of coming
| up with a false positive for _something_ start to approach
| 1!
| captainmuon wrote:
| But the tests are not binary sick or healty. If your test
| gets more sensitive, then you have to shift the, say, PSA
| value that you use for a diagnosis.
|
| I really _hope_ that false positives become a regular
| thing. For one it shows that the tests are working
| according to statistics.
|
| Second, getting comfortable with false positives means
| that you can more easily hold off treatment, if in your
| specific scenario the treatment is not beneficial - think
| an old test that doesn't find the cancer plus a new test
| that does; and the new test is shown to lead to
| overtreatment. We need to learn when to hold on and _not_
| to treat.
|
| And third, if testing for 10 things will find something
| that you don't want to know and harm your psyche, when
| you test for 100 things you will have almost certainty
| that there is a false positive and this can give you back
| some of the "blissfull ignorance" I believe (while the
| doctor can still give you the statistically best
| treatment).
| TaupeRanger wrote:
| The only problematic mindset is yours, and you clearly have
| not engaged with the subject of iatrogenics in any
| meaningful way. The policy you advocate for would cause
| real harm to real people, likely to no benefit. Please
| understand how wrong you are.
| athenot wrote:
| > _" Our tests are bad, so lets[sic] not test" is not a
| thought worthy of respect._
|
| Correct. But that's not the issue here.
|
| Current tests can detect benign tumors, and do. People go
| in for their regular tests, hear "cancer" and of course
| want to get treatment. But that treatment itself is not
| idempotent. You want to accept the negative side-effects if
| the alternative is an aggressive cancer that will end your
| life soon. But you don't want that if there is no cancer.
|
| As in many fields, it's a matter of trade-offs and risk
| assessment.
|
| Here's one article detailing some of the issues surrounding
| overdiagnosis of colorectal cancer:
|
| https://www.gastrojournal.org/article/S0016-5085%2818%29348
| 2... (2018)
| pessimizer wrote:
| You're advocating for a policy that may kill or hurt more
| people than the alternative, and insisting that doing the
| math is reprehensible.
|
| The enemy is not cancer, the enemy is ill-health and death.
| You could cure all deaths from cancer by poisoning everyone
| with cyanide.
| colinmhayes wrote:
| The public health literature has been over this again and
| again. Over zealous non-symptomatic testing consistently
| leads to worse outcomes. You can get as philosophical as
| you want, the fact remains that it lowers total utility.
| plank_time wrote:
| The utter confidence with how you answer all these comments
| while being completely wrong is sickening. It really shows a
| lack of vision but you wield your confidence like an expert
| but you're not and only displaying the Dunning-Kruger to a t.
|
| Early detection these days consists of things like CT scans
| which can't tell the difference between cancerous tumors and
| benign tumors. I have a friend with a mass near her liver but
| they didn't detect it until quite large. She asked what she
| should do and their answer was "well if it was liver cancer
| you would be dead by now, so it must be benign."
|
| This is the state of detection that you think is such a
| utopia, that we shouldn't bother trying to improve, because
| you are so confident with your answers but you literally have
| no idea how wrong you are.
|
| Having an accurate blood test that can differentiate a
| cancerous tumor from benign is ground breaking. Early
| detection of cancers like pancreatic or liver cancer
| detection is virtually impossibly today until it's too late
| is groundbreaking. It could lead to new treatments that work
| when the cancer is small vs when it's too big to operate.
|
| You're taking studies done using very obtuse, inaccurate and
| costly detection like MRIs and CT-Scans and conflating them
| with new technologies. It's backwards, old thinking and
| trying to pooh-pooh new ideas and technologies because of
| poor understanding on your part. It had no place here among
| people with vision and hope for the future.
| andai wrote:
| I expect this won't catch on until it becomes a wearable
| technology, and then it will catch on overnight.
| zrail wrote:
| That's already a thing, at least everywhere I've ever lived.
| You have a primary care doctor, you see them at least once a
| year, they do a physical exam, maybe some blood work. This test
| maybe becomes standard of care for everyone annually.
| reacharavindh wrote:
| May be I have been living in a bubble. I remember doing a
| "annual check up" in the US about 5 years ago, and that was
| super basic - blood pressure, sugar, cholesterol levels etc.
| they didn't even do a detailed enough bloodwork to test for
| allergies. Definitely not looking for any disease vectors.
|
| Now, I live in DK, and my visit to the GP would always go
| with my hard attempts to convince my GP that something is
| really wrong and I am not a crazy lunatic who is simply
| looking for attention. Although, I have never directly asked
| for a checkup(while being healthy) to look for disease
| vectors. I'll ask and see what they say.
|
| I'd prefer if this is outside of the general healthcare
| system though. I don't want to occupy Doctors, and medical
| labs from people who are actually sick _now_ and need those
| tests, and attention.
| msrenee wrote:
| I don't think blood tests for allergies are a regular thing
| anywhere. It's generally done if you can't have the skin
| testing and the skin testing is something you go to a
| specialist for. It's not something that's screened for
| regularly.
| flemhans wrote:
| Another Danish person here, your GP would never check you
| in any sort of fashion here, unless you already have
| (serious) symptoms.
| refurb wrote:
| This approach actually works really well for conserving
| healthcare dollars. If a doctor feels like nothing is
| wrong, 99% of the time they'll be right. Sucks to be that
| 1% where you die of a cancer that would have been caught,
| but that's the trade off.
|
| The marginal return of each dollars spent on screening goes
| down quickly. At a population level you can't justify it,
| but at a personal level you can.
| horstmeyer wrote:
| Same for me in Germany. You are eligible to one checkup
| when you turn 35, that's it, lol. Otherwise you have to
| convince the doctor a certain check is necessary. Usually
| doctors don't like that very much. I would even happily pay
| for it myself, but I still need to convince the doctor I'm
| not a hypochondriac.
| moooo99 wrote:
| Thats not true. The cost of the checkup are covered once
| before you turn 35 and every three years for anybody
| above the age of 35 [1]. Still, people have to be willing
| to do that checkup, make an appointment by themselves and
| so on.
|
| Still, seeing what is and what isn't covered by public
| health insurance just seems so stupid. The focus on cure
| instead of prevention, and that not even particularly
| good. It's sad to see how much money goes to waste for
| useless treatments with something like homeopathy while
| people who really need proper treatment are stuck with
| the cheapest option that is paid for.
|
| [1]
| https://www.bundesgesundheitsministerium.de/checkup.html
| (German)
| horstmeyer wrote:
| Thanks for the correction, that was what my doctor told
| me. But maybe I also misunderstood him.
| vmception wrote:
| That's not good enough for cancer because we dont even know
| how fast or slow it grows. Even if it cancer cells multiplied
| at the rate of a fetus that would be too fast for an annual
| physical. Congratulations, death.
|
| Ideally something like a wearable computer or nanomachines in
| your blood stream automatically report anomalies for
| individualized treatment.
| danuker wrote:
| > Even if cancer cells multiplied at the rate of a fetus
|
| I suspect at least some cancers multiply slower than that,
| because they work against the rest of the cells.
| dryrun wrote:
| Given the amount of "I don't want bill gates injecting me a
| tracker!", I have some idea of how a conversation with the
| same people about nano machines in their body would go.
|
| I would also bet on the time-frame between this and the
| availability of your data on the servers of your health
| insurance.
| vmception wrote:
| Not my problem, human cancers stay in there own bodies
| and are not communicable
|
| To our knowledge
| jacquesm wrote:
| Not normally, no. But there are some puzzling exceptions:
|
| https://www.discovermagazine.com/health/the-cancers-that-
| are...
| vmception wrote:
| These are all in animals and I specified human cancers
| for that specific reason, thanks for the article though,
| I only knew about the Tasmanian Devil one
| jacquesm wrote:
| Yes, correct. But there are also some viruses that cause
| cancer that can spread from human to human (HPV for
| instance, the cause of cervical cancer), and the case of
| that doctor is some proof that at least in theory cancer
| can spread by blood or tissue contact.
| postingawayonhn wrote:
| I've never lived anywhere where this was common. The public
| health system can't afford to fund it and most of the
| population doesn't want to (or can't afford to) pay for it
| themselves.
| Clampower wrote:
| This is not true in the Netherlands. You don't get any tests
| if there is nothing wrong.
|
| Healthcare in this country scares me.
| danuker wrote:
| In the US, the medical system was (and might still be) the
| top third cause of death, of which 5/6ths were due to
| medicine side-effects.
|
| https://nutritionfacts.org/video/how-doctors-responded-to-
| be...
|
| I suspect doctors in the Netherlands are taught not to
| over-diagnose. Are they paid through national insurance?
| goodpoint wrote:
| Yes, the US medical system is a disaster.
| pelorat wrote:
| You can ask for a blood test though and ask that they check
| specific markers. But I agree that huisartsen are too
| dismissive in general.
| egeozcan wrote:
| Same in Germany (Hausarzte). Even if you have a specific
| complaint, you'll just be told to go home and drink a lot
| of water. They just don't have the capacity to test for
| causes.
|
| I'm not sure if I can even pay someone to make extensive
| tests here. Never tried. Perhaps one needs to go to the
| US for that.
| the-dude wrote:
| Take control. Regular doctors in NL are basically there to
| prevent you from getting care.
|
| Say you want a blood test, and what for. I they don't
| cooperate, move to the next doctor.
| RGamma wrote:
| FWIW there's self-service blood tests with capillary blood
| at e.g. medivere.
|
| Tried to do the cholesterol one, but couldn't get the blood
| into the tube _shrug_
| msrenee wrote:
| No mammograms? No pap smears? No prostrate screening?
| That's shocking.
| jacquesm wrote:
| We do all of those, but they're all voluntary (as they
| should be), there are regular drives for all of these.
| refurb wrote:
| Really? Not even a blood pressure check or a physician
| listening to your lungs or just examine your skin for weird
| moles?
|
| That's terrible.
| the-dude wrote:
| I am leaving my current physician because I had a very
| strange, black patch on my back, surrounded by a
| 'bleached', growing circle.
|
| Due to COVID, I provided videos to her assistant, which
| the physician reviewed. Physician claimed she needed
| better pictures ( obviously I had sent the best material
| ).
|
| The response to that was : the doctor needs to see the
| patch herself.
|
| Then when I arrived at the appointment she basically
| treated me like shit. I have filed a complaint with her
| practice.
|
| This is NL.
| mpfundstein wrote:
| my experience is totally differe t. just sayin
| Tolyzz wrote:
| Cause things break down all the time. And everything can look
| like early signs of trouble.
|
| There are lot useless docs and surgeons waiting to perform
| unnecessary expensive procedures much like building
| contractors. Oh that pipe is leaking let's just replace this
| entire load bearing wall etc cause we have this new cool
| machine that can. Second opinions are over rated cause the
| majority don't care. There is an endless demand for their
| trade.
|
| My dad lost his hearing at 35 after they performed surgery to
| remove a tumor they detected. They detected the same Tumor in
| my brother when he was in his 20s and wanted to operate with no
| guarantee of hearing preservation. He declined. He is going to
| turn 40 soon and would have most likely been deaf for 20 years
| if he had gone through with it. Minor issues with his balance
| but other than that he is fine even though tumor gets tracked
| every couple years and is still growing.
| BallyBrain wrote:
| This sounds like a regulation and education problem to me.
|
| early detection doesn't have to mean treatment, it could just
| be monitoring and change of lifestyle.
| xwdv wrote:
| My experience is people don't really care much about their
| bodies beyond the aesthetics. Most treat it like a dumpster and
| ingest whatever crap feels good and hope for the best. Caring
| too much makes you some sort of health freak in their eyes,
| with way too much time on your hands.
| danuker wrote:
| The top risk factors for death confirm what you say, sadly.
|
| https://ourworldindata.org/causes-of-death#the-number-of-
| dea...
| carlmr wrote:
| I'm not sure this is true. At least in my friend circle most
| people put a lot of care into their nutrition and fitness.
|
| Maybe talk to your friends about it and get them to be
| healthier?
| handrous wrote:
| How do you think we get the rates of diabetes and obesity
| we have in the US, without that being true for _most
| people_ in most places and in most social circles? Rich
| social networks tend to live much healthier lifestyles than
| average. Normal is fried starch and tens to hundreds of
| ounces of soda more days than not, and exercise is that
| maybe you golf sometimes or play in a seasonal company
| softball league (drinking way more calories than you 're
| burning, almost certainly).
| INGSOCIALITE wrote:
| Theranos?
| aembleton wrote:
| This test probably needs a lot more blood than a single drop.
| xiphias2 wrote:
| Galleri test looks great, but it is available only in US and UK.
| I wish they would allow private patients in other countries to
| take the test somehow.
| giantg2 wrote:
| If it's detecting 50 types of cancer and the patient doesn't have
| symptoms, do they just do a full body MRI to find the source? If
| so, why not just do full body scans which can find other issues,
| like aneurysms or the other almost 50% of positives that it
| missed?
|
| I get that cost is a big issue, but it seems like the test is
| missing a lot and you might get more bang for the buck with a
| periodic MRI from the perspective of the number of potential
| issues it can find. Either way can result in false results.
| elif wrote:
| I mostly agree. I had a CT scan of 1/3 of my body for a
| specific issue, but as a consequence I got very high confidence
| that I was cancer-free in that portion of my body. It is such a
| good feeling that part of me wants to pay out-of-pocket to get
| the rest checked.
|
| I think though that this test has massive value in earlier
| detection, cost, and remote lab work.
| giantg2 wrote:
| Dude, CTs can be risky. They use ionizing radiation, which
| increases your risk of cancer. It's really only an issue with
| repeated use, but I think there's a study out there claiming
| 50k early deaths each year can be attributed to repeated use
| of CTs. I don't have any medical background, but personally I
| would prefer imaging that does not use ionizing radiation
| when possible, just to save up some "credits" for when I may
| need to use the other type (like CT for possible stroke).
| doctoring wrote:
| Hey, radiologist here.
|
| So, the question of "what next" after a positive result on one
| of these tests is still... open. The Grail test provides
| indication of likely tissue of origin, so a likely first step
| may be a targeted study (e.g. colonoscopy if it said a colonic
| source, MRI if it said pancreatic). There may be role for
| PET/CT as well to further stage and assess for metastases,
| perhaps after finding a lesion.
|
| What to do if your blood test is positive but the workup is
| negative? Lots of discussion but nobody is quite sure.
|
| As for a periodic full body MRI, I will say that currently uh,
| most of those are garbage. Unfortunately, for a full body MRI
| to be practical (that is, to not take hours and hours), you
| have to run very few sequences. (For example, a dedicated MRI
| of say, your brain or your liver _alone_ could take about hour,
| each.) As a result, you greatly reduce your sensitivity for
| most pathologies, which kind of is counter to the point of the
| MRI to begin with.
| giantg2 wrote:
| Oh, so the test does give the source. I must have missed that
| part of the article thinking it was only identifying that
| there was a source in the cfDNA that was abnormal, but not
| realizing they could determine where it came from.
| bookofjoe wrote:
| What makes this even more revolutionary to me (retired
| anesthesiologist) is that the methodology allows for use of
| Theranos-style finger-prick-size blood samples rather than IV
| blood draw, since fragment identity is the indicator rather than
| level/concentration.
| wgolsen wrote:
| The concentration of cell free DNA in blood plasma is generally
| in the nanograms/mL range, meaning most cfDNA assays will
| require at least a ~mL of plasma input for sufficient
| sensitivity / reproducibility. We aren't quite at the capillary
| blood level of sensitivity yet.
| [deleted]
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