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The only randomised trial of screening colonoscopy cut bowel cancer by 18 percent because only 42 percent of the people invited turned up. A test that is 20 percent more sensitive but is taken by the same people buys far less than an invitation that 20 percent more people accept.
NordICC randomised invitations rather than procedures, and reported a ten-year colorectal cancer risk of 0.98 against 1.20 percent, a number needed to invite of 455, and no difference in all-cause mortality; 11,843 of 28,220 invited (42.0 percent) attended. Nottingham had already shown the same pattern with a cheaper test: 40.4 percent of the screening group never completed a single kit, and 400 of 893 cancers in that arm presented in non-responders. Kaminski's data add the second half: an endoscopist's adenoma detection rate, not the offer itself, determines whether the colonoscopy that follows a positive test prevents anything.
The screening age is the other live question. The United States moved to 45 in 2021 on the strength of Siegel's birth-cohort analysis, and 20 percent of United States cases are now in people under 55. No randomised evidence exists for the extension; the decision rested on modelling, and the capacity cost falls on the same endoscopy services that are already the constraint.
The numbers behind the argument that the screening programme is working for the people it covers and failing everyone below its start age; the stage shift going into reverse is the most uncomfortable figure on this roadmap.
Colonoscopy screening works, but the effect a health system gets is the effect of the invitation, not of the procedure; uptake, not test performance, is the binding constraint, and this is the trial that made that argument unavoidable.
The first molecular stool test to reach approval, and the template for the blood tests that followed: more sensitive for cancer, much less specific, and still poor at the precancerous lesions that screening is supposed to remove.
The paper that made the adenoma detection rate the central quality measure of every screening endoscopy service, and the reason endoscopist-level auditing is a condition of accreditation.
The evidence that a cheap home test posted to a whole population saves lives, and the reason England, Scotland, Wales and Northern Ireland all run bowel screening programmes; the 40 percent who never did the test are the reason uptake is still the biggest lever.
Shares AI polyp detection in colonoscopy, Quality indicators for colonoscopy and the risk of interval cancer, Effect of colonoscopy screening on risks of colorectal cancer and related death (NordICC), Colonoscopy and the tag colorectal-evidence.
Shares Quality indicators for colonoscopy and the risk of interval cancer, Effect of colonoscopy screening on risks of colorectal cancer and related death (NordICC), Colonoscopy, Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood) and the tag colorectal-evidence.
Shares Colorectal cancer statistics, 2023, Colonoscopy, Faecal immunochemical test (FIT), Early-onset colorectal cancer (under 50) and the tag colorectal-evidence.
Shares Randomised controlled trial of faecal-occult-blood screening for colorectal cancer (Nottingham), Faecal immunochemical test (FIT), Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood), The hardest cancers are found late and the tag colorectal-evidence.
Shares Colorectal cancer statistics, 2023, Early-onset colorectal cancer (under 50), Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood), Prevention we already have is not deployed and the tag colorectal-evidence.
Shares Early-onset colorectal cancer (under 50), Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood), Prevention we already have is not deployed, The hardest cancers are found late and the tag colorectal-evidence.
Shares Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood), Prevention we already have is not deployed, The hardest cancers are found late, Colorectal cancer roadmap: from the adenoma-carcinoma sequence and the first screening trials to total mesorectal excision, oxaliplatin, RAS testing, immunotherapy for mismatch repair-deficient disease, ctDNA-guided treatment and organ preservation and the tag colorectal-evidence.
Shares Early-onset colorectal cancer (under 50), Prevention we already have is not deployed, The hardest cancers are found late, Colorectal cancer roadmap: from the adenoma-carcinoma sequence and the first screening trials to total mesorectal excision, oxaliplatin, RAS testing, immunotherapy for mismatch repair-deficient disease, ctDNA-guided treatment and organ preservation and the tag colorectal-evidence.