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Comment by lucioperca | Hacker News Reader

Is there evidence that people benefit from the colonoscopy or FIT at all? Or does overtreatment and risk of the procedure outweigh any benefit?

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My understanding has always been that colonoscopy is long proven to be one of the highest benefit ratio procedures in all of medicine. Let me see if there's a solid source for that... OK, here's the American College of Surgeons fact sheet - https://www.facs.org/~/media/files/education/patient%20ed/co...

Unambiguously stating that up to 90% of polyps or the tumors they grow into can be detected and removed. Also that lifetime risk of these cancers is 4.5%, versus a low risk of complications from the procedure. Compare to much lower detection rates for non-invasive procedures, and note that a positive from a FIT or FOBT will get you a referral for... a colonoscopy.

I don't have any expertise here, only marginal interest, and hoping like hell that it always stays that way. But it's not comforting to read that the odds of a serious horror show are higher than flipping a coin and getting heads 5 times in a row. Seems unlikely but do you want to bet your life on it?

Also not comforting to see the low rate of detection for the lab tests. FOBT misses 2 to 4 out of 10. FIT misses 97% of advanced cancer? That must be a typo. Checking... "FIT has been extensively evaluated for screening, with sensitivity estimates of a single low-threshold FIT for CRC approaching 90%." (https://gut.bmj.com/content/68/9/1642) But of course, that's once you have something that bleeds. The scope finds those earlier.

All very unnerving. A lot depends on the goal: catch your own cancer early, which suggests getting a scope early, or increase detection broadly among a population, which suggests focusing on easy-to-take tests that more people complete.

sorry, in all this doom, what do you suggest is the best way to detect? I had hopes on FIT until you pointed the 97% out.

Huge disclaimer: I don't know much of anything more about this than I've already said herein, but the basic info seems fairly easy to find and parse.

  - A colonoscopy will detect *most* precursor or active anomalies.
  - A FIT or FOBT will detect *many* active anomalies once they are bad enough to start releasing traces of blood.

What's plain from even a quick read of the info out there is that national health systems and big insurers can't afford to do colonoscopies on everyone, so they have a huge interest in these lower cost lab tests. If enough people take them, then the headline can be "we caught more cancer earlier, and helped a lot of people". But "helped" means things like surviving a few years, which, thanks, but that's not the same as surviving full stop.

As an individual, a lab test is way better than nothing, but if your health system or insurance will cover the cost, or if you can afford to pay for it out of pocket, then a colonoscopy will reveal most problems, even fairly early and small ones, and give the surgeon a chance to snip out polyps and such right then and there. If the scope comes back reasonably clear, you can be 10 years until the next one.

Keep in mind there is a low risk of "serious complications" (one paper concludes ~2.8 per 1000) or death (~0.34 per 1000) from the colonoscopy procedure. If you'd like to have nightmares about it, source is https://www.giejournal.org/article/S0016-5107(11)01965-1/pdf

Please, anyone, correct me if anything there isn't a fair generalization.

thank you for the TLDR

The goal is longer survial or more disability-adjusted life years. The sources as far as I see do not really tell us much better we do with a colonoscopy every 10 years for a total of 3 times in your life than without.

> Compared with no endoscopic screening, receipt of a screening colonoscopy was associated with a 67% reduction in the risk of death from any colorectal cancer (adjusted OR (aOR)=0.33, 95% CI 0.21 to 0.52). By cancer location, screening colonoscopy was associated with a 65% reduction in risk of death for right-colon cancers (aOR=0.35, CI 0.18 to 0.65) and a 75% reduction for left-colon/rectal cancers (aOR=0.25, CI 0.12 to 0.53).

http://dx.doi.org/10.1136/gutjnl-2016-312712

As a rule of thumb, the earlier it is detected, the better any type of cancer is treatable.

My impression is that colonoscopy is less controversial than other forms of screening, even among people who tend to see cancer screening very critical.

The USPSTF tends to advise against cancer screenings without good evidence, and they are positive about colonoscopy: https://uspreventiveservicestaskforce.org/uspstf/draft-recom...

https://uspreventiveservicestaskforce.org/uspstf/recommendat... A link to the current recommendation (2016) since the other one is still in progress.

There's good evidence that removing polyps prevents cancer. So the subset of people that have polyps benefit a lot.

I think that one advantage is that the procedure it's not only for screening but preventive. They use it for, at the same time they are checking for problems, remove polyps, that can be precursors of cancer.

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