Screening for colorectal cancer.

: This paper reviews studies on fecal occult blood testing and sigmoidoscopy screening for colorectal cancer. Recently published data from a randomized controlled trial provides the first concrete evidence that annual screening for fecal occult blood can reduce colorectal cancer mortality by at least 33%. These results are corroborated by a nonrandomized but controlled study that showed a 43% colorectal cancer mortality reduction with early detection through fecal occult blood testing and sigmoidoscopy, and by a case-control study that showed a 31% colorectal cancer mortality reduction associated with fecal occult blood testing. Persuasive data to support screening recommendations for sigmoidoscopy are not yet available; however, results from observational studies are suggestive and should stimulate further research to assess the benefit of sigmoidoscopy screening.