Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial

摘要: Summary Background Colorectal cancer is the third most common worldwide and has a high mortality rate. We tested hypothesis that only one flexible sigmoidoscopy screening between 55 64 years of age can substantially reduce colorectal incidence mortality. Methods This randomised controlled trial was undertaken in 14 UK centres. 170 432 eligible men women, who had indicated on previous questionnaire they would accept an invitation for screening, were randomly allocated to intervention group (offered screening) or control (not contacted). Randomisation by sequential number generation done centrally blocks 12, with stratification centre, general practice, household type. The primary outcomes cancer, including prevalent cases detected at from cancer. Analyses intention treat per protocol. registered, ISRCTN28352761. Findings 113 195 people assigned 57 237 group, whom 112 939 57 099, respectively, included final analyses. 40 674 (71%) underwent sigmoidoscopy. During median follow-up 11·2 (IQR 10·7–11·9), 2524 participants diagnosed (1818 vs 706 group) 20 543 died (13 768 6775; 727 certified [538 189]). In intention-to-treat analyses, reduced 23% (hazard ratio 0·77, 95% CI 0·70–0·84) 31% (0·69, 0·59–0·82). per-protocol adjusting self-selection bias attending 33% (0·67, 0·60–0·76) 43% (0·57, 0·45–0·72). Incidence distal (rectum sigmoid colon) 50% (0·50, 0·42–0·59; secondary outcome). numbers needed be screened prevent diagnosis death, end study period, 191 (95% 145–277) 489 (343–852), respectively. Interpretation Flexible safe practical test and, when offered once ages years, confers substantial longlasting benefit. Funding Medical Research Council, National Health Service R&D, Cancer UK, KeyMed.