Colon cancer screening. Sigmoidoscopy or colonoscopy

Colorectal cancer is a common neoplasia with high morbidity and mortality. With endoscopy it is possible to identify its precursor lesion, the adenoma, and early localized cancer. Early detection and removal of adenomas can reduce the incidence and mortality of this disease. Studies using fecal occult blood testing (FOBT) and sigmoidoscopy for screening asymptomatic patients demonstrate a reduction in mortality from colorectal cancer. Colonoscopy, however, has the highest yield for detecting polyps. Most authorities and organizations now recommend screening the asymptomatic population over age 50 for colorectal neoplasia. The estimated cost of colon cancer screening is well within the benchmark figure of $40,000 per year of life saved, which is considered by the government to be cost effective. Controversies still exist regarding which colon cancer screening strategy is the most sensitive, specific, acceptable to the population, and cost effective. The American Cancer Society recommends a combination of FOBT and flexible sigmoidoscopy, but some experts believe that a one-time colonoscopy at age 60 may be a more cost-effective method. If the costs of colonoscopy are reduced, it is more cost effective than other techniques. Colonoscopy also may help to stratify at-risk patients, and those with negative initial colonoscopy may not need further screening. Advances in molecular biology may provide markers for screening or identifying people who are at high risk for colorectal neoplasia. This development may allow screening to be directed at high-risk groups.