Colon cancer screening of average risk populations can reduce mortality from colorectal cancer (CRC), reduce cancer incidence, and has been shown to be cost-effective in the United States. The most effective screening test is uncertain. After patients are discovered to have neoplasia, colon surveillance is recommended. Surveillance is a costly part of colon screening programs, and the appropriate intervals for surveillance are uncertain. There is evidence that the majority of patients with adenomas could have extended intervals between surveillance exams, which would reduce cost and risk.