Efficacy, effectiveness and cost-effectiveness of endoscopic screening methods.

Epidemiological evidence suggests that incidence of colorectal cancer can be reduced by 60-90% among participants of preventive colonoscopy with removal of precancerous lesions. Even with sigmoidoscopy, the majority of cancers can be prevented. Cost-effectiveness analyses suggest screening schemes based on colonoscopy every 10 years or on sigmoidoscopy every 5 years to be highly cost effective compared to other preventive measures. Even higher cost-effectiveness is to be expected if screening intervals can be extended to 20 or more years, as suggested by recent epidemiological evidence.