Screening Flexible Sigmoidoscopy and Colonoscopy Are Associated with Less Colorectal Cancer and Lower Mortality

How effective is screening with flexible sigmoidoscopy or colonoscopy in preventing colorectal cancer and colorectal cancer–associated death? Investigators addressed this question in this systematic review and meta-analysis of randomized, controlled trials (RCTs) and observational studies from the U.S., Canada, and Europe.

In four RCTs, researchers assessed screening flexible sigmoidoscopy versus no endoscopy in 438,000 participants. In intent-to-screen analyses, sigmoidoscopy lowered colorectal cancer–related mortality significantly (by 22% to 31%); pooled estimates of risk reduction were 18% for colorectal cancer incidence and 28% for colorectal cancer–related mortality. For distal colorectal cancer, sigmoidoscopy lowered incidence and mor…