[HN Gopher] Cancer survival rates are misleading
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Cancer survival rates are misleading
Author : speckx
Score : 60 points
Date : 2025-10-28 17:59 UTC (1 days ago)
(HTM) web link (www.allendowney.com)
(TXT) w3m dump (www.allendowney.com)
| deadfoxygrandpa wrote:
| this article is trivial nonsense. of course he's technically
| correct, but the article contains no useful information and boils
| down to just saying that people (including doctors) aren't
| looking at literally only 5 year survival rate charts.
|
| like the colon cancer thing. he talks about how it would only be
| more effective to catch colon cancer early if you assume we have
| treatments for it that would work early. but we don't need to
| just assume blindly. we already know we do have those treatments!
| jplusequalt wrote:
| Yeah, not sure what the point here is. Could see someone who
| reads this and comes away thinking that a cancer screening
| isn't worth it.
| connorshinn wrote:
| Agreed. I think his blog title, "Probably Overthinking It", is
| appropriate named.
|
| Essentially every assertion in the article is either an
| oversimification, cherry picking a random niche situation to
| highlight, or just flat out factually inaccurate.
|
| Let's take this paragraph for example:
|
| "Catching cancer early is beneficial only if (1) the cancers we
| catch would otherwise cause disease and death, and (2) we have
| treatments that prevent those outcomes, and (3) these benefits
| outweigh the costs of additional screening. This table does not
| show that any of those things is true."
|
| To address these one by one:
|
| 1. Obviously cancer causes disease and death. The same graphic
| he references makes that abundantly clear. Sure, there might be
| some rare exceptions (elderly patients with slow growing colon
| cancer for example), but we're talking about the general
| population.
|
| 2. All cancers have treatment options available in some form
| (could be chemo, radiation, surgical resection, etc), so this
| assumption doesn't even make sense to include. Let's assume for
| a second though that treatments might not be available. Even if
| that were true, there ARE treatments that can help treat cancer
| symptoms, and but may not affect the tumor directly. Often
| these are specific to the specific type of cancer.
|
| 3. This assertion is dumb - is the author really trying to
| argue that providing symptomatic or other relief to a cancer
| patient isn't a sufficient benefit to warrant additional
| screening?
|
| I could go on, but you get the point. Some people just like
| arguing for the sake of arguing I guess.
| ian-g wrote:
| Of course they're misleading. What did the doctor tell us when my
| mom was diagnosed? Don't do research, do not trust Dr. Google,
| Dr. Google lies. At best, Dr. Google is behind the times.
|
| The specifics of your case will strongly affect what happens to
| you. And even for cancers that are a guaranteed death sentence,
| survival has increased significantly in recent years.
| nyeah wrote:
| I think this is a technical article about a narrow aspect of
| public health policy, not advice to individual patients.
|
| One point in the article is that early detection would give you
| more years to live even if there were no treatment. Because
| "early" means "more years". This wasn't obvious to me right away.
|
| But he is _not saying_ don 't get screened! He is not saying
| there are no cancer treatments! He's saying that the 5-year
| survival rate, considered alone, is a tricky measure that can
| fool our intuition. In my case he's right.
|
| ---------------------
|
| Details.
|
| Dumb toy model. Let Tumor X kill you exactly 8 years after it
| becomes detectable in screening. Assume screening is 100%
| accurate with no false positives. Assume X cancer kills you
| exactly 2 years after it causes symptoms. Imagine that there is
| no treatment for X cancer.
|
| In this dumb model, everybody dies at exactly the same time after
| the tumor became detectable. The people who caught it in
| screening had more warning, but otherwise they didn't get a
| better outcome. Even though screening boosts the 5-year survival
| rate from 0% to 100%.
|
| Never mind his like 7-state Markov model. OMG. Why.
| dkural wrote:
| This article, in the world as it exists right now, is wrong about
| colon cancer. Anyone reading this of a certain age: get that
| colonoscopy, and those polyps removed. Snip it in the bud. That's
| the great thing about a colonoscopies - all-in-one screening +
| treatment.
|
| Evidence: https://www.nejm.org/doi/full/10.1056/NEJMoa1301969
|
| Large prospective cohorts (Nurses' Health Study + Health
| Professionals Follow-Up Study) with long follow-up - screening
| colonoscopy was associated with a 68% lower risk of death from
| colorectal cancer overall (multivariable HR [?] 0.32, 95% CI
| 0.24-0.45) and showed significant reduction for proximal colon
| mortality as well (HR [?] 0.47, 95% CI 0.29-0.76).
| travisjungroth wrote:
| > For colon cancer, the rates from the SEER data are are 91%,
| 74%, and 16%.
|
| This is the only claim the article makes directly about colon
| cancer. Otherwise, it's saying that early detection being
| beneficial isn't supported by survival rates alone.
| nyeah wrote:
| "Otherwise, it's saying that early detection being beneficial
| isn't supported by survival rates alone."
|
| That claim may be obvious to everybody except me. Anyway it
| turns out to be true.
| gruez wrote:
| >To be clear, all of these conclusions can be true, and in some
| cases we know they are true, at least in part. For some cancers,
| treatments have improved, and for some, additional screening
| would save lives. But to support these conclusions, we need other
| methods and metrics - notably randomized controlled trials that
| compare mortality.
|
| the economist put out a piece a few months ago providing just
| that. Specifically it compares overall cancer mortality rates
| (and more interestingly, mortality rates adjusted for age) and
| shows that cancer deaths have been dropping.
|
| https://www.economist.com/briefing/2025/07/17/the-world-is-m...
|
| https://archive.is/TNjoi
| mr_toad wrote:
| > notably randomized controlled trials that compare mortality.
|
| Putting people into a control group so you can observe the
| effects of not treating them might not make it past the ethics
| committee.
| WorkerBee28474 wrote:
| You don't not treat the control group. You give the control
| group the current standard treatment, and you give the
| experimental group the new trial treatment.
| gus_massa wrote:
| Now everyones agree with you and there are no more cases like
| https://en.wikipedia.org/wiki/Tuskegee_Syphilis_Study
| (hopefuly).
|
| In the current trials a part of the subjects get the new
| experimental drug and the control group get the current state
| of the art treatment.
| mr_toad wrote:
| Yes, but when you compare treatments A vs B for trial 1,
| and then B vs C for trial 2, and then C, vs D for trail 3,
| you might not get the same results as comparing A vs D,
| especially when there may have been other changes in
| between the three trials (different ages, lifestyles etc).
|
| This is a real problem when the Minister wants to know if
| it's worth spending money on treatments, because all you
| have is a disjointed set of trials, none of which are
| necessarily representative of the population at large, or
| the population wide incidence of the disease (assuming
| there is even data on that (notifiable illnesses are the
| exception).
| standardUser wrote:
| Randomized controlled trials are a bummer of a 'gold standard'.
| Extremely expensive, extremely slow and in many cases
| absolutely impossible. I'm not an AI true believer, but I do
| hope it offers an alternative or at least enables some
| desperately needed efficiencies.
| bonsai_spool wrote:
| The site, in very elaborate ways, is saying that Stage IV cancer
| (in the author's words 'tumor has spread to distant organs or
| lymph nodes') is worse than Stage I (localized) cancer.
|
| I don't think there is any person who is aware of the idea of
| cancer mortality who would equate 'Stage IV' to lead to 'average'
| survival.
|
| So maybe the article's only point (which is very obvious, and
| does not require Markov modeling) is that if you increase the
| number of people who live a long time in a sample, then the
| average of that sample will go up.
|
| This feels like someone saw a fact on the internet and didn't try
| to read about it before writing a blog post.
| travisjungroth wrote:
| This article is a criticism of reasoning, not health advice or
| suggestions for cancer screening. Maybe he should put a big
| warning at the top, rather than explain it throughout. A lot of
| people seem to be missing it.
|
| We're so used to argument that criticizing logic is taken as
| criticizing the conclusion.
| tptacek wrote:
| The only thing the author seems to be directly arguing against
| is speculative full-body MRI scanning, which is already
| mainstream medical advice, for many of the reasons he offers.
| DebtDeflation wrote:
| Near as I can tell, the only valid point the author makes is that
| since mortality rates increase as cancer progresses stages and
| since progression through stages takes time, a 5 year mortality
| rate is not a great metric and it would be better to also have 10
| and 15 year mortality rates to determine the degree to which
| early detection + treatment actually increases life expectancy.
| dullcrisp wrote:
| Also, and I can't tell if this point is made, but cancers that
| are more progressed are more likely to be detected without
| screening, so extra screening may just increase the proportion
| of cancers that were never going to be deadly that are
| detected.
| standardUser wrote:
| > Because it is based on past cases, it doesn't apply to present
| cases if (1) the effectiveness of treatment has changed or -
| often more importantly - (2) diagnostic practices have changed.
|
| This was my key takeaway. In a society organized around
| statistics, we're struggling through an era where those
| statistics expire faster everyday, and faster than new data can
| be generated. I can almost relate to the mindset that devalues
| "facts" because they're increasingly complicated, rapidly
| changing and come with too many caveats.
| tptacek wrote:
| Weirder still that Taleb misses the base rate flaw in the logic
| of full-body MRI screening and cancer screening, an observation
| that is pretty up his alley and is kind of a well-known thing in
| this domain.
| 1970-01-01 wrote:
| So their entire argument is statistics does not tell the entire
| story. Didn't we all learn this truth when we learned statistics?
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(page generated 2025-10-29 23:01 UTC)