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Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

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Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#191

Post by sokoloff »

thaumasiotes wrote: post #188
sokoloff wrote: post #181

Earlier quoted context omitted.

It seems to me with electronic medical records that you could do population-wide studies using data that already exists (and I think that would pass IRB, or at least "ought to"). That would likely tell you "for the patients matching criteria X (are covered by BCBS and live in state X, or whatever), the 10 year outcome for patients who turned 50 in 2010 was Y vs Z conditioned on whether they had a colonoscopy".

What would you be trying to learn from that? You're comparing unlike groups. You can't draw any conclusions.

If I look at all people born in 1960, living in NY, covered by BCBS, that’s a like group.

If I then split by “had a colonoscopy between 2008 and 2012, inclusive” vs “didn’t” and look at 2012 through 2021 outcomes to draw conclusions, it’s possible that that filtering makes them unlike groups (I mean, it definitionally does in at least the primary selection criteria). Given that the effort is approximately that of a SQL query, I’d be interested to know if there’s a possible signal there, which would need to be corroborated with other data sets to determine the repeatability of the correlation and then if there’s any likely causal link.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#192

Post by gilbetron »

wellbehaved wrote: post #176
gilbetron wrote: post #94

Earlier quoted context omitted.

Beware Vinay Prasad: https://www.respectfulinsolence.com/2022/07/27/john-ioannidi...

Beware David Gorski: https://stevekirsch.substack.com/p/how-david-gorski-defends-...

Beware Steve Kirsch:

https://www.technologyreview.com/2021/10/05/1036408/silicon-...

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#193

Post by alexjpb »

Irresponsible click bait title. If you are over 40,take a colonoscopy. I lost my brother (44) from colon cancer which could have been totally prevented. It was a very painful and depressing experience, multiple rounds of chemotherapy and surgeries that lasted over four years and sent his family into bankruptcy. He stopped eating solid foods weighing only 47 kilos and died from suffocation, pretty much liquid accumulating and pressing against his lungs until he could no longer breath. It's a slow and horrible dead that can be prevented with a simple one hour procedure done once every 5-10 years and in many cases 100% covered by insurance.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#194

Post by dahart »

timr wrote: post #144
dahart wrote: post #139

Earlier quoted context omitted.

> Though this sounds counterintuitive, it’s the “gold standard” because, if you don’t do this, you leave yourself open to bias Isn’t there just as much chance for bias if the treatment is voluntary? Maybe the people who are more likely to have health issues are less likely to treat them. I think there is a valid question about how effective a colonoscopy is given that you get one, and a separate valid question about…

> Isn’t there just as much chance for bias if the treatment is voluntary? I'm not quite sure what you're asking here. If you're wondering if voluntary opt-out of colonoscopy carries risk of bias, then I'll say the following: it's an intervention that is painful, intrusive and time consuming. No reasonable person would get one absent demonstrated benefit. Pick a thing where people are reasonably likely to do it as def…

> No reasonable person would get one absent demonstrated benefit.

But if we insist on measuring demonstrated benefit by factoring in participation rates, then it’s a catch-22. What if given a prior distribution of 100% opt-in, colonoscopies are effective? And you ignored my question about what if we made colonoscopies more convenient, less intrusive and time consuming, which is becoming possible with new tech. These things can change the participation rate, which in turn can flip the outcome from little demonstrated benefit to high and conclusive demonstrated benefit.

> this study did the fairest possible test for effectiveness of colonoscopies

“Fair” is a subjective term, and it depends on what question you’re asking. I agree with your statement if the question is how effective is the current system of recommending colonoscopies. It’s not the fairest test of how effective a colonoscopy screen could be if everyone shows up for the screen. Colonoscopies might be not better than genetic tests because participation rates for genetic tests are higher, as opposed to colonoscopy screening being less effective on their own.

I understand your point that the total probability is important. But so is understanding the Bayesian factors, it’s equally enlightening and important to separate and understand the effectiveness of the screen given participation, from the likelihood of participation. And you effectively cemented how important this point is by clarifying that people use knowledge of these outcomes in order to choose whether or not to participate, so framing them incorrectly can and likely does lead to unnecessary loss of life.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#195

Post by FinnLeSueur »

theptip wrote: post #153
dis-sys wrote: post #68

Earlier quoted context omitted.

as reported by the article, an impressive 50% reduction of cancer death for those who did colonoscopy. I call that solid evidence which could potentially save millions of real lives.

Not reported, how many people died from side effects of the procedure, such as blood poisoning/infection. We care about all-cause mortality, not cancer mortality.

I haven't read the article - only the abstract, but it does report: "No perforations or screening-related deaths occurred within 30 days after colonoscopy." I guess something could have happened later than 30 days but we'd need the full article for that.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#196

Post by thaumasiotes »

JamesBarney wrote: post #159
sokoloff wrote: post #45

Earlier quoted context omitted.

If colonoscopies are helpful to avoid negative outcomes, but invitations to colonoscopies are not, looking into making invitations better seems like an obvious play to me.

The problem is you can't run a study on colonoscopies that doesn't involve an invitation without forcing people to get a colonoscopy at gun point. Which would both be illegal and never pass an IRB.

> Which would both be illegal and never pass an IRB.

To be fair, this is not two separate problems. Anyone who's willing to run the illegal study will not care whether they can get IRB approval.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#197

Post by ldoughty »

jrochkind1 wrote: post #97
ldoughty wrote: post #72

Earlier quoted context omitted.

> The problem with the title is that it might lead individuals to believe they shouldn't bother with getting a colonoscopy. That is exactly what I thought it was saying at a glance. If I skimmed the headline and moved on, instead of digging in, it might have contributed to an unconscious bias against the procedure.

Uh... I think it is what it's saying though? I mean, you should probably still get a colonoscopy if recommended by your doctor which it probably will be right now... but the effects of this study may be to change those recommendations down the line, that is what it suggests. (I think it's not the first, but I'm not sure).

The summary I read on CNN:

> In this study, about 12,000 people in Sweden, Poland and Norway got colonoscopies. They saw a 31% reduction in their risk of colon cancer and a 50% reduction in their risk of dying from colon cancer compared with people who were not invited to get a colonoscopy.

https://www.cnn.com/2022/10/10/health/colonoscopy-study-q-an...

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#198

Post by 1123581321 »

brooklyndude wrote: post #112

I’m unique guess in the world. We’re all going to die. If you make it to 57, awesome. After that it’s all a bonus. Take that attitude, and you really don’t put off much. You don’t turn down any invites. And do wake up with the Sun. Life is awesome! Don’t be so afraid of death. It’s not that bad. Really. Source: survived an NDE. Was not my time was told, but did get a great tour of the afterlife. Don’t worry so much.…

I like your attitude, but it's hard to apply it to loved ones as cavalierly!

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#199

Post by wellbehaved »

gilbetron wrote: post #192
wellbehaved wrote: post #176

Earlier quoted context omitted.

Beware David Gorski: https://stevekirsch.substack.com/p/how-david-gorski-defends-...

Beware Steve Kirsch: https://www.technologyreview.com/2021/10/05/1036408/silicon-...

"He prefers iconoclastic approaches, whether by directly funding asteroid detection or advocating for nuclear power to combat global warming."

Ooh, scary dude. /s

Kids nowadays. I remember when nuclear power was a futuristic clean energy sort of ideal and when the way we figured out who was right and who was wrong on a complex topic was to let both sides openly debate and then pick who is more credible by how each is able to rally the facts in defense of their position.

Beware your society, which is doing the same thing to people like Kirsch that it did to Socrates two thousand years ago. The masses never change, apparently. All that changes is whether they're held in check or whether they're exploited by demagogues.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#200

Post by timr »

dahart wrote: post #194
timr wrote: post #144

Earlier quoted context omitted.

> Isn’t there just as much chance for bias if the treatment is voluntary? I'm not quite sure what you're asking here. If you're wondering if voluntary opt-out of colonoscopy carries risk of bias, then I'll say the following: it's an intervention that is painful, intrusive and time consuming. No reasonable person would get one absent demonstrated benefit. Pick a thing where people are reasonably likely to do it as def…

> No reasonable person would get one absent demonstrated benefit. But if we insist on measuring demonstrated benefit by factoring in participation rates, then it’s a catch-22. What if given a prior distribution of 100% opt-in, colonoscopies are effective? And you ignored my question about what if we made colonoscopies more convenient, less intrusive and time consuming, which is becoming possible with new tech. These…

> What if given a prior distribution of 100% opt-in, colonoscopies are effective?

That is what the "per-protocol" analysis in this RCT estimates. They considered only those people who had a colonoscopy. This completely breaks randomization and is subject to investigator bias, but at least it gives you an idea of the best you could possibly do if you lived in a world where everyone was forced to get one.

And that is: a drop of 0.15% in colo-rectal death. They then attempt to extrapolate this to estimate the effect on all-cause mortality if you somehow forced everyone to get a colonoscopy, and come up with a number of 10.88% (vs. a baseline of 11.03%). So, even if you forced everyone to get a test, you'd need to test 667 people to save one life.

That's a lot of pain for very little gain.

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