[CrazyStat]

> Small clarification - early detection is most often curative and cheap.

> It actually provides a pretty good incentive for insurers to cover screening and early detection beyond what is mandated by law.

The evidence in favor of mass screening programs in the hope of early detection is actually weak to non-existent [1].

> In total, 2 111 958 individuals enrolled in randomized clinical trials comparing screening with no screening using 6 different tests were eligible. Median follow-up was 10 years for computed tomography, prostate-specific antigen testing, and colonoscopy; 13 years for mammography; and 15 years for sigmoidoscopy and FOBT. The only screening test with a significant lifetime gain was sigmoidoscopy (110 days; 95% CI, 0-274 days). There was no significant difference following mammography (0 days: 95% CI, −190 to 237 days), prostate cancer screening (37 days; 95% CI, −37 to 73 days), colonoscopy (37 days; 95% CI, −146 to 146 days), FOBT screening every year or every other year (0 days; 95% CI, −70.7 to 70.7 days), and lung cancer screening (107 days; 95% CI, −286 days to 430 days).

There are large institutions, both nonprofit and commercial, which stand to gain by convincing people that mass screening is useful and important. The available scientific evidence does not support their position.

[1] https://jamanetwork.com/journals/jamainternalmedicine/fullar...

[haldujai]

You’re looking at the wrong metric and misinterpreting the stats, not only is overall survival not a good metric for cancer screening none of the studies are sufficiently powered for OS.

What you want to do is look at stage at presentation, treatment costs by stage, and screening costs. These were done for nearly every recommended screening program.

The available evidence behind currently recommended screening programs unequivocally shows improved cancer-specific survival and earlier stage at diagnosis.

[CrazyStat]

I'm going to strongly push back on both (1) the notion that overall survival is the wrong metric and (2) that I'm misinterpreting something, given that I didn't really offer any interpretation at all. I just cited a paper.

> What you want to do is

No, what I want to do is assess whether broad screening programs actually make people live longer. Overall survival is the correct metric. Evidence in favor of the claim is lacking.

> none of the studies are sufficiently powered for OS.

"Sufficiently powered" is relative to what size of effect you want to detect--which you haven't specified, so I'm not sure how you can make the assertion that none of the studies are sufficiently powered.

> The available evidence behind currently recommended screening programs unequivocally shows improved cancer-specific survival and earlier stage at diagnosis.

These outcomes ignore negative effects of screening on people who don't have cancer, which is why I'm not interested in them. And yes, there are negative effects, and no, they are not negligible.

[haldujai]

> No, what I want to do is assess whether broad screening programs actually make people live longer. Overall survival is the correct metric. Evidence in favor of the claim is lacking.

Correct according to whom? If you want to choose only one metric quality adjusted life years is likely the best one.

While OS may be your goal that's not the primary endpoint of screening programs.

Some examples of why OS is limited: breast lumpectomy vs mastectomy and systemic therapy or polypectomy vs neoadjuvant therapy and colonic resection are both associated with very high morbidity that is very important to patients. The vast majority of patients care about quality of life.

> "Sufficiently powered" is relative to what size of effect you want to detect--which you haven't specified, so I'm not sure how you can make the assertion that none of the studies are sufficiently powered.

We do not expect any one screening program to have a large change on overall survival because there are many ways to die, very few studies are powered to detect the small differences expected. The reference below does some modeling and discusses cancer-specific vs all-cause mortality for your perusal.

https://onlinelibrary.wiley.com/doi/full/10.1002/cam4.2476

> These outcomes ignore negative effects of screening on people who don't have cancer, which is why I'm not interested in them.

See morbidity discussion around delayed diagnosis above.

> And yes, there are negative effects, and no, they are not negligible.

As you're choosing to limit the discussion to overall survival, do you have any data to support the claim that screening has more than a negligible negative effect?

There is a better argument to be made for other harms of screening like cost and stress but if we want to discuss these negative effects of screening we also have to step back from overall survival and discuss morbidity benefits.

ETA:

> 2) that I'm misinterpreting something, given that I didn't really offer any interpretation at all.

This is your interpretation, and is an incorrect one:

> The evidence in favor of mass screening programs in the hope of early detection is actually weak to non-existent [1].

The evidence you cite says nothing about early detection and treatment paradigms.

[CrazyStat]

> Correct according to whom? If you want to choose only one metric quality adjusted life years is likely the best one

By all means, if you have studies showing that broad screening programs are beneficial in terms of overall (not cancer-case only) QALY then please share them. I'm guessing you don't.

> As you're choosing to limit the discussion to overall survival, do you have any data to support the claim that screening has more than a negligible negative effect?

Do you have any data to support the claim that screening has more than a negligible positive effect on overall survival? (No).

Stop trying to put the burden of proving a negative on me. If you want to advocate for spending ten of billions of dollars annually (not to mention time and stress) on broad screening programs you bear the burden of demonstrating that's useful.

If we can afford to spend the money on screening everyone certainly we can afford to spend less money to run a large randomized trial screening only some people, but advocates of the screening programs won't stand for it because they are convinced of their own righteousness and refuse to admit uncertainty about whether the screening programs are actually doing more good than harm.

[haldujai]

> By all means, if you have studies showing that broad screening programs are beneficial in terms of overall (not cancer-case only) QALY then please share them. I'm guessing you don't.

I gave you one.

> Stop trying to put the burden of proving a negative on me.

You're making the claim there's more than a negligible negative effect not me.

> Do you have any data to support the claim that screening has more than a negligible positive effect on overall survival? (No).

Did I say there is a sizable positive effect on overall survival? I said it's irrelevant.

[CrazyStat]

> I gave you one.

No you didn't, you gave me a simulation study that discussed what kind of sample size might be necessary to find statistically significant effects in all-cause mortality. There's not a single mention of QALY in there. Please stop misrepresenting things.

> You're making the claim there's more than a negligible negative effect not me.

The cost itself is a nonnegligible negative effect.

> Did I say there is a sizable positive effect on overall survival? I said it's irrelevant.

You're wrong.

It's borderline fraud, in my humble opinion, to go around suggesting that massive interventions should be evaluated based on their effects only on the people who benefit most, ignoring the negative effects on the other 98% of the population. Which is exactly what you did in your first reply to me:

> What you want to do is look at stage at presentation, treatment costs by stage, and screening costs. These were done for nearly every recommended screening program.

> The available evidence behind currently recommended screening programs unequivocally shows improved cancer-specific survival and earlier stage at diagnosis.

This approach to evaluating an intervention is intellectually dishonest and emotionally manipulative. Any evaluation that does not take into account the other 98% of the population--through overall survival or QALY or some other metric--is giving an extremely biased picture of what the intervention is actually doing to the population as a whole.