Interrupting the adenoma-carcinoma sequence: screening for adenomas and cancer, now and in the future.

Screening for colorectal cancer is only beginning to receive the attention it deserves. As screening emerges into the mainstream and utilization increases, competing technologies will battle to assume a greater percentage of the market share of testing. In this review, the standards and principles with which screening tests are evaluated are outlined. Current modalities for screening, including fecal occult blood testing (FOBT), flexible sigmoidoscopy, colonoscopy, barium enema, and the combination of FOBT with sigmoidoscopy, are discussed and critically reviewed. New techniques and technologies for screening, including virtual colonoscopy and molecular methods of screening stool, are previewed. Increased attention on screening and the competition for supremacy among the modalities undergoing evaluation make the prospects for a continued diminution in colorectal cancer mortality promising.