The findings, along with a second study reported in Thursday's New England Journal of Medicine , deepen doubts about the reliability of sigmoidoscopy. Both sigmoidoscopy and colonoscopy use a flexible tube that is inserted in the rectum to examine the large intestine for cancerous or precancerous polyps. Sigmoidoscopy, which reaches only part way up the colon, is commonly used for checking patients at no special risk for colon and rectal cancer, which killed about 56,000 people in the United States last year. There will definitely be lives saved with colonoscopy in average-risk patients, and I think there's going to be increasing attention paid to it.'' Colon and rectal cancer killed about 56,000 people in the United States last year.
Colorectal cancer is second only to lung cancer in causing cancer deaths.
About 130,000 cases were diagnosed last year. Tearing and other serious bleeding, though rare, happen more often with colonoscopies. In sigmoidoscopy, the tube is inserted only about two feet up the colon. The device shows the colon on a video screen and removes any worrisome growths. If such growths are found, a colonoscopy will usually be performed later to examine the entire colon, which snakes up about five feet to the small intestine.