Inclusion Criteria:  consecutive patients aged ≥50 years undergoing colonoscopy are eligible for enrollment.  Exclusion Criteria:  high risk family history of colorectal cancer (CRC) e.g., familial adenomatous polyposis, hereditary non-polyposis CRC syndrome, multiple first degree relatives with CRC, or a single first degree relative with CRC at <60 years serrated polyposis syndrome inflammatory bowel disease colonoscopy to remove a large neoplastic polyps obstructive lesions of the colon gastrointestinal bleeding current participation in other studies hospitalized patients mental retardation pregnancy refusal to provide a written informed consent.