Incidental finding of colorectal cancer in screening colonoscopy and its cost effectiveness.

The objective of this study is to measure the risk of colorectal cancer and adenoma with screening colonoscopy and its cost effectiveness. We reviewed the procedure and pathology results of approximately 11,000 asymptomatic patients age 50 to 90 that underwent screening colonoscopy. Among those 11,808 screening colonoscopies performed, advance neoplasm (adenocarcinoma) was detected in 272 (2.3%) patients; age 50 to 90, with mean age of 64-years-old. Fourteen per cent had hyperplastic polyps, 15 per cent had tubular adenoma, and 8.6 per cent villous adenoma. Adenoma with high grade dysplasia was found in 6.6 per cent, and 5.5 per cent had nonadenomatous lesions. Sixty-five of 272 (24%) neoplasms were found proximally. Forty-five of 207 distal neoplasms were found through sigmoidoscopy, nine of 45 (20%) had proximal involvement. Rate of complication during colonoscopy was 0.06 per cent and no patients died. All patients underwent complete colonoscopy, 99.8 per cent were men. Rate of adenocarcinoma from 2000 to 2006 was (24/470, 29/520, 33/891, 37/961, 46/2889, 49/2977, and 54/3100). Screening colonoscopy can detect advanced colorectal neoplasm in asymptomatic adults. The more screening colonoscopy was preformed the earlier the neoplasm was discovered and with better prognosis. Twenty per cent of the patients with distal neoplasms found on sigmoidoscopy had proximal lesions when complete colonoscopies were performed. These findings warrant refinement of the screening recommendations for colorectal cancer.