Colorectal cancer screening.

Colorectal cancer is the second most lethal cancer in the United States. The lifetime risk of developing colorectal cancer in the United States is 5%. Early detection decreases mortality, and involves stratifying individuals by risk factors. Clinicians can use several methods for detection and surveillance of colorectal cancer including the digital rectal exam (DRE), fecal occult-blood test (FOBT), flexible sigmoidoscopy, colonoscopy, and double contrast barium enema. Several groups offer guidelines recommending specific screening techniques and intervals. In general, a combination of an annual FOBT and a flexible sigmoidoscopy every 5 years is recommended for average-risk individuals. Colonoscopy is the gold standard for visualizing the entire colon, and is reserved for abnormal findings on FOBT or flexible sigmoidoscopy or for individuals of greater-than-average risk for colorectal cancer.