COMMUNITY SCREENING FOR COLORECTAL-CANCER

Preventive programs for colorectal cancer (CRC) should ideally start w ith an assessment of risk of the subject. Choice of screening procedur es should be personalized for those of above average risk, i.e. those with a familial incidence of CRC, personal history of colorectal neopl asia or inflammatory bowel disease. For average-risk subjects, case-co ntrol studies indicate that screening by sigmoidoscopy seems capable o f reducing risk of death from cancer within reach by about 60%. The fi rst reported randomized controlled study of occult blood testing has s hown a 33% reduction in mortality from CRC (all sites). Provided that additional controlled, population-based trials nearing completion also show a significant reduction in CRC mortality, then large-scale commu nity-based screening programs for average-risk subjects will be justif iable. The value of colonoscopic screening at a community level is unc lear; it seems likely that compliance will be very low and cost effect iveness unsatisfactory. No controlled trials using colonoscopy as the primary screening method have been conducted. Those with no obvious ri sk factors apart from age over 50 years may reasonably be screened by annual faecal occult blood testing (preferably with new, more sensitiv e tests) and 5-yearly sigmoidoscopy (flexible if possible).