US Preventive Services Task Force. Sigmoidoscopy in the periodic health examination of asymptomatic adults

PERIODIC screening sigmoidoscopic examination of asymptomatic persons has been recommended for more than 30 years¹⁻³as a means of reducing mortality from colorectal cancer. However, evidence supporting this recommendation is limited and expert opinion, as reflected in several recent reviews,⁴⁻⁸differs as to whether sigmoidoscopy should be included in the periodic health examination. Colorectal cancer, with a cumulative incidence of 5.1% in men and 3.9% in women by age 74 years,⁹is the second leading cause of cancer mortality in the United States. More than 145 000 new cases and 61000 deaths from this disease are expected for 1987.¹⁰Thus, screening tests that can lead to earlier detection and improved survival are needed. In addition to earlier detection, screening sigmoidoscopy may reduce the incidence of colorectal cancer through removal of premalignant adenomatous polyps. In evaluating sigmoidoscopy as a screening test, it is important to distinguish between