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Most cancer screenings don’t extend life, study finds

cnn.com

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Re: Most cancer screenings don’t extend life, study finds

#71

Post by burnished »

twoodfin wrote: post #62
burnished wrote: post #57

Earlier quoted context omitted.

The article quotes some one saying this isnt a call to abandon screenings in totality. The risks are not 'car crash from doctors visit' they are 'got cancer from imaging', 'unnecessary surgery and complications', etc - the risks are directly related to the screening. This is an active topic in medical ethics as well which you seem ignored of (no offense intended), given that you are framing this in terms of insurance…

I’m not arguing that all screenings are worthwhile, or that the questions you raise aren’t vital to answer for good medical practice. I’m arguing that this specific analysis has very little to tell individuals about how they should perceive the value of any particular test. A different analysis—looking at the particular negative outcomes of the testing itself or the reaction to false positives—would be a different st…

I see! Who are you arguing against? The article gives zero indication that any of this is actionable, seems to advocate not changing anything with respect to your regular medical care.

But to answer your question; 'nothing'. This is interesting but it isn't actionable.

Re: Most cancer screenings don’t extend life, study finds

#72

Post by HWR_14 »

francisofascii wrote: post #27
somenameforme wrote: post #13

Earlier quoted context omitted.

The paper [1] is more well written and clear than the CNN article. They were comparing the aggregate life expectancies of people who went through regular screenings vs those who did not, and there was near zero difference except for colorectal screenings where the difference was about 4 months of difference. The paper is indeed presenting strong evidence that regular screenings have minimal value. [1] - https://jaman…

> except for colorectal screenings where the difference was about 4 months of difference That sounds, uh, significant. So to clarify, does that mean people gain 4 months on average by getting this screening? Those who get the cancer gain years, and those that don't gain 0, so the average is 4 months?

That is how I read it.

It also makes me wonder that if some cancers are rare enough to average to 0 months (rounded down) that could still work out to a 1/500 chance of living to 80 vs 40. Long odds it matters, but big difference if it does.

Re: Most cancer screenings don’t extend life, study finds

#73

Post by kazinator »

LorenPechtel wrote: post #65
kazinator wrote: post #15

Earlier quoted context omitted.

If we decrease premature deaths from any cause, particularly a common cause of premature deaths, we increase life expectancy. Or just what do the authors think life expectancy means? It's an average. Every premature death drags down average life expectancy. If we say that cancer screening has no effect of life expectancy, that's exactly the same as saying that it doesn't prevent premature deaths. If cancer screening…

No, because we might be replacing one cause with another. That's what they've found with PSA--it kills (via treating things that wouldn't actually have killed the patient) as many as it saves.

> That's what they've found with PSA--it kills (via treating things ...)

I'm not sure what PSA you're referring to. The Prostate-Specific Antigen PSA is something secreted by the body, and not a treatment, so it can't be that one.

Are you referring to overdiagnosis (via PSA or any other screening), resulting in overtreatment?

Re: Most cancer screenings don’t extend life, study finds

#74

Post by DennisP »

pessimizer wrote: post #36
DennisP wrote: post #23

Earlier quoted context omitted.

Yes but as someone else mentioned, it's like an insurance policy. Buying insurance doesn't make you richer on average, it makes the insurance company richer. But you aren't guaranteed the average outcome, so it's still rational to get the insurance, to cover the cases where you'd otherwise have a catastrophic loss. As with gambling, it's not just about expected value. You also have to consider risk of ruin.

False positives can be debilitating or fatal.

But at what rate? The study doesn't say.

Re: Most cancer screenings don’t extend life, study finds

#75

Post by rocmcd »

Retric wrote: post #16
monero-xmr wrote: post #7

An excellent episode of EconTalk came out today on this very subject: Open: https://simplecast.econtalk.org/episodes/vinay-prasad-on-can... Apple: https://podcasts.apple.com/us/podcast/econtalk/id135066958?i... Highly recommend the episode and show. The gist is that cancer is only 4% of deaths, and screening only reduces those 4% by 20% (so it does not help whatsoever 80% of cancers). But there is a lot more to the e…

Those numbers seem really off. The US has 3,464,231 deaths per year with cancer killing just over 600k, so 17.3%. https://www.cdc.gov/nchs/fastats/deaths.htm https://www.cancer.org/research/cancer-facts-statistics/all-... Also cancer screenings happen in the US. Thus 750k deaths without screenings and 80% of that = 600k deaths with screenings and 150k deaths postponed. Are they using some unusual definition or someth…

The 4% GP quoted was in reference to individual cancers (since there is no "cancer" screening, each screening is specific to a type of cancer).

I'm having trouble finding numbers, but the comment by Vinay was basically saying that each screening is testing for something that has 1-4% chance of killing you. Not that 4% of all cause mortality is cancer, which is incorrect. In the context of individual screenings per cancer, the numbers roughly make sense based on what I could find, but I am by no means an expert.

The specific video/content they are rehashing is the one by Vinay here - https://www.youtube.com/watch?v=-9hQO7X1bmU

I'd highly recommend listening to the Econtalk conversation as there is a lot of nuance behind why screenings (at least as they are done today) could potentially be a net negative at the individual level and don't seem to have improved all-cause mortality in a significant way (according to Vinay).

Re: Most cancer screenings don’t extend life, study finds

#76

Post by DennisP »

idopmstuff wrote: post #54
throwway120385 wrote: post #42

Earlier quoted context omitted.

Given that screening is arguably benign for most people, you could argue that we continue screening while we gather more information. But you do whatever you want to do. I'm just pointing out that it's really premature to cancel all of your screenings based on the idea that it doesn't add any years to your life. That may be true, but there's more to a life than how long you live.

> Given that screening is arguably benign for most people You're 100% wrong here, this is not a given. Prostate cancer screenings, which are very common, can have both false positives as well as findings of cancer that is and would remain completely benign. These can both lead to unnecessary treatments that cause serious negative health effects, including incontinence and erectile dysfunction. https://www.cdc.gov/can…

So work the numbers. Put together the chance of false positives, false negatives, rate of negative effects from treatment, and rate of death with and without treatment. Tell the patient the risk of each outcome.

The math is easy. If we don't have the numbers for it, then get them. Plenty of people get prostate cancer and some of them choose to just monitor. We should have plenty of information to make a rational decision. This seems preferable to blinding ourselves out of fear that we'll do something stupid with the information we might get.

Re: Most cancer screenings don’t extend life, study finds

#77

Post by pintxo »

idopmstuff wrote: post #54
throwway120385 wrote: post #42

Earlier quoted context omitted.

Given that screening is arguably benign for most people, you could argue that we continue screening while we gather more information. But you do whatever you want to do. I'm just pointing out that it's really premature to cancel all of your screenings based on the idea that it doesn't add any years to your life. That may be true, but there's more to a life than how long you live.

> Given that screening is arguably benign for most people You're 100% wrong here, this is not a given. Prostate cancer screenings, which are very common, can have both false positives as well as findings of cancer that is and would remain completely benign. These can both lead to unnecessary treatments that cause serious negative health effects, including incontinence and erectile dysfunction. https://www.cdc.gov/can…

It’s important to note that it’s not the screening causing those issues. It’s the fact that our health care systems are rather inadequate in properly handling those screening results at the margin.

Re: Most cancer screenings don’t extend life, study finds

#79

Post by twoodfin »

burnished wrote: post #71
twoodfin wrote: post #62

Earlier quoted context omitted.

I’m not arguing that all screenings are worthwhile, or that the questions you raise aren’t vital to answer for good medical practice. I’m arguing that this specific analysis has very little to tell individuals about how they should perceive the value of any particular test. A different analysis—looking at the particular negative outcomes of the testing itself or the reaction to false positives—would be a different st…

I see! Who are you arguing against? The article gives zero indication that any of this is actionable, seems to advocate not changing anything with respect to your regular medical care. But to answer your question; 'nothing'. This is interesting but it isn't actionable.

I thought the article was pretty sloppy in its description of the results. Here’s the lede:

Most cancer screenings don’t ultimately give someone extra time beyond their regular lifespan, according to a new review of clinical trials involving more than 2.1 million people who had six kinds of common tests for cancer.

This is trivially misreadable as “an individual with cancer who catches it early via screening doesn’t see appreciable lifespan benefits”, which is decidedly not what the analysis purports to show.

The use of “someone” makes me question whether the author of the CNN article understood the analysis in the first place. The phrase “extra time” is also particularly strange, since it’s something of a loaded term in the world of serious disease. I don’t get a cancer screening because I want “extra time”. I look to get on the early-access list for an unapproved chemo drug because I want “extra time”. The article goes on to frame the results in a way that easily could be misunderstood to be the benefits for sick patients to early detection rather than the average benefits across the entire population, sick and healthy.

Re: Most cancer screenings don’t extend life, study finds

#80

Post by idopmstuff »

DennisP wrote: post #76
idopmstuff wrote: post #54

Earlier quoted context omitted.

> Given that screening is arguably benign for most people You're 100% wrong here, this is not a given. Prostate cancer screenings, which are very common, can have both false positives as well as findings of cancer that is and would remain completely benign. These can both lead to unnecessary treatments that cause serious negative health effects, including incontinence and erectile dysfunction. https://www.cdc.gov/can…

So work the numbers. Put together the chance of false positives, false negatives, rate of negative effects from treatment, and rate of death with and without treatment. Tell the patient the risk of each outcome. The math is easy. If we don't have the numbers for it, then get them. Plenty of people get prostate cancer and some of them choose to just monitor. We should have plenty of information to make a rational deci…

> Tell the patient the risk of each outcome.

This isn't a simple problem of calculating EV. Telling somebody that there's a 40% chance that the positive test is actually wrong and in the 60% case that it's right, 40% of the time it's going to be benign, but if it's not benign it might kill them but if it is benign and they do surgery they might be left wearing diapers is not a simple thing for a person to evaluate. Add to that the fact that people have a bias towards action, so doctors tend to overindex on treatment vs. just ignoring something, and you have an incredibly complex problem.

> The math is easy.

No, it's not. It's a series of probabilities combined with extremely subjective outcomes (getting erectile dysfunction may have a very different impact on your life if you're 40 vs. 80).

> If we don't have the numbers for it, then get them.

You're just trivializing medicine and medical research here. Why don't you just go ahead and build some AI that'll solve this whole problem by diagnosing cancers based on a blood sample? That seems easy enough.

> This seems preferable to blinding ourselves out of fear that we'll do something stupid with the information we might get.

Ironically what you're describing here is the opposite of everything you've just talked about. If we understand the numbers well, and from those we can conclude that tests are highly prone to false positives and thus that treatment based on positive results is more likely to be harmful than helpful, then we shouldn't take those tests. That's not blinding ourselves, it's acting appropriately based on understanding the math.

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