{"entity":{"id":"paper-atkin-once-only-flexible-sigmoidoscopy-lancet-2010","kind":"paper","name":"Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial","aka":[],"tldr":"One look at the lower bowel with a short scope, offered once between 55 and 64, cut bowel cancer cases by a quarter and deaths by a third in a UK trial of 170,432 people.","summary":"The UK Flexible Sigmoidoscopy Trial, run in 14 UK centres by Atkin, Edwards, Kralj-Hans and colleagues, randomly allocated 170,432 men and women who had said on a previous questionnaire that they would accept screening to be offered one flexible sigmoidoscopy or not to be contacted at all. Randomisation was in blocks of 12, stratified by trial centre, general practice and household type. The primary outcomes were colorectal cancer incidence, including cases found at screening, and colorectal cancer mortality.\n\n40,674 of the 57,099 people in the intervention group (71 percent) underwent the test. Over a median 11.2 years, 2,524 participants were diagnosed with colorectal cancer and 727 deaths were certified from it.","asOf":"2026-09-24","links":[{"label":"Lancet 2010","url":"https://doi.org/10.1016/S0140-6736(10)60551-X"},{"label":"PubMed","url":"https://pubmed.ncbi.nlm.nih.gov/20430429/"}],"tags":["colorectal-evidence"],"related":["paper-atkin-flexible-sigmoidoscopy-17-year-follow-up-lancet-2017"],"cancers":["colorectal"],"sections":["early-detection","prevention"],"technologies":["colorectal-screening","endoscopy"],"targets":[],"drugs":[],"companies":[],"institutions":["cruk"],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":["b-early-detection","b-prevention-adoption"],"keyPapers":[],"journals":["lancet"],"dependsOn":[],"notes":[],"journal":"The Lancet","year":2010,"doi":"10.1016/S0140-6736(10)60551-X","pmid":"20430429","authors":"Atkin WS, Edwards R, Kralj-Hans I, et al.","paperType":"rct","findings":["Intention to treat: colorectal cancer incidence reduced by 23 percent (hazard ratio 0.77, 95 percent CI 0.70 to 0.84) and mortality by 31 percent (0.69, 0.59 to 0.82).","Per protocol, adjusted for self-selection: incidence reduced 33 percent (0.67, 0.60 to 0.76) and mortality 43 percent (0.57, 0.45 to 0.72).","Distal colorectal cancer incidence halved (0.50, 0.42 to 0.59).","Numbers needed to screen to prevent one diagnosis 191 (145 to 277) and one death 489 (343 to 852)."],"whatItMeans":"The trial behind England's short-lived bowel scope screening programme, and the clearest demonstration that one endoscopic look, by removing adenomas, prevents cancer rather than only advancing its diagnosis.","caveats":["Participants had already said they would probably attend, so the trial population is more willing than a whole population.","Flexible sigmoidoscopy sees only the left colon, and the benefit was confined to distal cancers; right-sided disease, which is rising, is untouched.","England's bowel scope programme was discontinued and replaced by extending faecal immunochemical testing to younger ages."],"changedPractice":true,"participants":170432},"route":"/key-papers/paper-atkin-once-only-flexible-sigmoidoscopy-lancet-2010/","neighbours":{"paper":[{"id":"paper-atkin-flexible-sigmoidoscopy-17-year-follow-up-lancet-2017","kind":"paper","name":"Long term effects of once-only flexible sigmoidoscopy screening after 17 years of follow-up","route":"/key-papers/paper-atkin-flexible-sigmoidoscopy-17-year-follow-up-lancet-2017/"}],"cancer":[{"id":"colorectal","kind":"cancer","name":"Colorectal cancer","route":"/cancers/colorectal/"}],"section":[{"id":"early-detection","kind":"section","name":"Early Detection & Screening","route":"/fronts/early-detection/"},{"id":"prevention","kind":"section","name":"Prevention & Risk","route":"/fronts/prevention/"}],"technology":[{"id":"colorectal-screening","kind":"technology","name":"Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood)","route":"/technologies/colorectal-screening/"}],"term":[{"id":"endoscopy","kind":"term","name":"Endoscopy (EGD, EUS, ERCP)","route":"/terms/endoscopy/"}],"institution":[{"id":"cruk","kind":"institution","name":"Cancer Research UK","route":"/institutions/cruk/"}],"bottleneck":[{"id":"b-prevention-adoption","kind":"bottleneck","name":"Prevention we already have is not deployed","route":"/bottlenecks/b-prevention-adoption/"},{"id":"b-early-detection","kind":"bottleneck","name":"The hardest cancers are found late","route":"/bottlenecks/b-early-detection/"}],"journal":[{"id":"lancet","kind":"journal","name":"The Lancet","route":"/journals/lancet/"}],"roadmap":[{"id":"colorectal-roadmap","kind":"roadmap","name":"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","route":"/roadmaps/colorectal-roadmap/"}]}}