Single Colonoscopy or Two Series of Faecal Immunochemical Tests 2 Years Apart for Colorectal Cancer Screening (SCREESCO): Preliminary Report of a Randomized Controlled Trial
Screening for colorectal cancer is done by lower gastrointestinal endoscopy or stool-based tests. There is little evidence from randomized trials showing that primary colonoscopy reduces mortality in colorectal cancer. Our aim was to study the effect of screening with a single colonoscopy or two sets of fecal immunochemical tests on mortality and incidence of colorectal cancer.
Between March 1, 2014 and December 31, 2020, 278,280 people were included in the study; 31,140 were assigned to the colonoscopy group, 60,300 to the fecal immunochemical test group and 186,840 to the control group. 10,679 (35 1%) of the 30,400 people who received an invitation for a colonoscopy participated. 33,383 (55.5%) of 60,137 individuals who received a postal fecal immunochemical test participated. In the intent-to-screen analysis, colorectal cancer was detected in 49 (0.16%) of 31,140 people in the colonoscopy group versus 121 (0.20%) of 60,300 people in the fecal immunochemical test group (relative risk [RR] 0 78, 95% CI 0 56–1 09). Advanced adenomas were detected in 637 (2 05%) people in the colonoscopy group and 968 (1 61%) in the faecal immunochemical test group (RR 1 27, 95% CI 1 15–1 41) . Colonoscopy detected more advanced adenomas on the right side than fecal immunochemical tests. There were two perforations and 15 major bleeds in 16,555 colonoscopies. No procedure-related deaths occurred.
The diagnostic yield and low number of adverse events indicate that the design of this trial, both for single colonoscopy and fecal immunochemical test screening, could be transferred to a population-based screening service if a benefit on Disease-specific mortality is subsequently shown.
Swedish Regions, County Council, Regional Cancer Center Mellansverige, Swedish Cancer Society, Aleris Research and Development Fund, Eiken Chemical.