[timr]

> In the entire history of science, no claim meeting these criteria has ever been overturned, despite enormous opportunity for that to happen (if it were ever going to happen).

Yeah, that's just not true. It's an absurd claim. Medical science is loaded with examples of things that had wide consensus (but...95%? Probably? Feels like this is a loophole in the argument...) which were subsequently found to be false. Consider just a few examples:

* hormone replacement therapy

* aspirin for heart attacks

* mammograms for younger women (< 50)

Just this year, a huge RCT called into doubt the usefulness of mass colonoscopy [1], which was absolutely "scientific consensus" until now (you can see this, because the study was met with rather vicious backlash).

For a more basic science example, consider "The Central Dogma of Molecular Biology" [2] which, of course, was so "consensus" that they named it "The Central Dogma": genetic information goes from DNA to RNA to proteins.

This was fact...until they discovered retroviruses. Then prions. Oops.

This stuff happens all the time. The authors are either not scientists, or they're so blinkered by ideology that they're unreliable.

[1] https://www.nejm.org/doi/full/10.1056/NEJMoa2208375

[2] https://www.genome.gov/genetics-glossary/Central-Dogma

[tgv]

If you want another one: Alzheimer. The amyloid plaque theory was utterly dominant for 30 years. But the research led to nothing, the medicines that were developed don't work. This article was linked here recently: https://www.quantamagazine.org/what-causes-alzheimers-scient...

I'm sure there are theories in history, political science or sociology which once met the criteria, but are wrong. One of the things that (IMO!) is extremely important for something to be accepted as a fact is whether we can explain it through a causal model. The assumptions of such a model should at least meet the same criteria, but probably even stricter ones. A simple hand-waving explanation, no matter how widely accepted, should ever be accepted as fact.

[pdonis]

> Just this year, a huge RCT called into doubt the usefulness of mass colonoscopy [1]

This reference seems to be saying that mass colonoscopy reduces the 10 year risk of colorectal cancer by a statistically significant amount. How is this calling into doubt its usefulness?

[timr]

There was no significant survival benefit. Just because you find and treat cancer doesn't mean you've made someone's life better or longer.

> The risk of death from colorectal cancer was 0.28% in the invited group and 0.31% in the usual-care group (risk ratio, 0.90; 95% CI, 0.64 to 1.16). The number needed to invite to undergo screening to prevent one case of colorectal cancer was 455 (95% CI, 270 to 1429). The risk of death from any cause was 11.03% in the invited group and 11.04% in the usual-care group (risk ratio, 0.99; 95% CI, 0.96 to 1.04).

This isn't the final word on the subject, but it overturns the conventional wisdom that colonoscopy is an obvious win and worth all of the money, time, effort and pain we spend on it.

[nobody9999]

>This isn't the final word on the subject, but it overturns the conventional wisdom that colonoscopy is an obvious win and worth all of the money, time, effort and pain we spend on it.

I'd posit that the one in 455 people who would die without a colonoscopy would disagree that colonoscopy isn't worth "all the money, time, effort and pain we spend on it."

I would suggest that you ask my uncle about it, as he didn't have a colonoscopy and was eventually diagnosed with stage IV colorectal cancer.

But I won't make that suggestion, as it wouldn't be worthwhile -- because he's dead. From colorectal cancer.

I guess that what one person considers a waste of money, time, effort and pain, another might consider a worthy investment.

Currently, colonoscopy is the only way to confirm whether or not colorectal cancer (and/or pre-malignant polyps) is present.

I expect that eventually, we'll have a test for colon cancer, similar to the (PSA[0]) blood test that helps diagnose prostate cancer. But until then, colonoscopy is the only way to identify colorectal cancers.

For your part, I hope you never get cancer and live a long, healthy, happy life. But if you do end up with colorectal cancer, I hope you've disabused yourself of the ideas you've expressed and get yourself tested.

Good luck!

[0] https://www.cancer.gov/types/prostate/psa-fact-sheet

[timr]

> I'd posit that the one in 455 people who would die without a colonoscopy would disagree that colonoscopy isn't worth "all the money, time, effort and pain we spend on it."

Your post is a fantastic illustration of how and why we can't rely on "consensus" to determine fact. People routinely fall in love with narratives based on what they "know", and refuse to accept new data that challenges their narratives.

For literally anything we do, some people will die afterward. You could set up a study where you punch people in the shoulder at random, and follow them to see if getting punched implies a survival benefit. Eventually, everyone in both groups will die -- we'd expect about the same number in each group at any given time, because punching people in the shoulder probably doesn't affect lifespan. But still, people will die after getting punched!

Here we have a large, randomized study where approximately the same number of people died with colon cancer after getting colonoscopy as did without the screening. The screening had ~no effect on outcome.

Also, you've misunderstood: the 455 people is not the number of people who would die with colon cancer -- it's the number of perfectly healthy people you'd need to screen to prevent one case.

> I would suggest that you ask my uncle about it, as he didn't have a colonoscopy and was eventually diagnosed with stage IV colorectal cancer.

While I'm sorry for your loss, the data from this RCT suggests that colonoscopy on perfectly healthy people confers little to no survival benefit, and trumps any anecdote.

[nobody9999]

>Also, you've misunderstood: the 455 people is not the number of people who would die with colon cancer -- it's the number of perfectly healthy people you'd need to screen to prevent one case.

No. I haven't. If we don't do any colonoscopies, that 1 in 455 who develops colorectal cancer will die (as my uncle did) if the cancer isn't diagnosed early enough.

Don't want to go through the "trouble" of a colonoscopy after 50 years of age? Then don't. If so, I hope that you or anyone you love isn't that 456th person.

Yes, Anecdotes aren't data. However, that 1 in 455 is a statistic and what are statistics? Data based on aggregations of anecdotes.

I mentioned my uncle not because I want to pull your heartstrings. Rather, it's because while it's a simple thing to look at data and statistics, it's easy to forget that such data (at least in this case) breaks down in to anecdotes just like that one -- e.g., dead and/or very sick people -- who wouldn't be sick or dead with appropriate screenings.

If you don't care that some people will die without colonoscopies, that's your prerogative. I hope that attitude doesn't keep you or those you love from identifying potential colorectal cancer before it's too late.

That you don't care about others getting sick and dying[0] from the fourth leading cause of cancer deaths in the US, says something. Not sure what though and I won't speculate.

I'm sure that the your full-throated support for not doing colonoscopies is cold comfort to the (~36-56/100,000 Americans) ~118,000-185,000 actual, real people who develop colorectal cancer per year.

I'll say it one more time -- there are real people represented in that data. People who suffer and die every day. And if we did fewer colonoscopies, more of those people would, in fact, die, because their cancer wasn't diagnosed at all/soon enough. And so I have to put on my Quincy, M.E.[1] mask and ask: People are dying, doesn't anyone care? Is it correct to say that you don't care, or am I missing something?

It would be easy for me to just wish colorectal cancer on you and then ignore you, but I don't want you to get colorectal cancer (or cancer of any kind for that matter). Dying of cancer is a slow, agonizing, incredibly painful way to die and should be avoided as much as possible.

If you have a family history of colorectal cancer, please, please start having colonoscopies every two-five years starting at age 45.

If you don't, please do so every five years or so starting at age 50.

Or not. It's your life and (eventually) your funeral. That's up to you.

[0] https://gis.cdc.gov/Cancer/USCS/#/Trends/

[1] https://en.wikipedia.org/wiki/Quincy,_M.E.

Edit: Fixed references and closed emphasis asterisk.

[BlackFly]

An ongoing theme in cancer research with regards to diagnostics is that a lot of the cancers caught by the diagnostic techniques would not be fatal. Hence, there is not a statistically significant reduction in mortality but rather a reduction in cancer. It is basically just saying: not all cancers kill you, maybe you are better off not knowing about the non-fatal ones.

Part of the backlash points out that cancer can affect quality of life in other ways and no one measured that. But either way, it throws the consensus into doubt.