Risk of advanced colorectal neoplasm according to the number of adenoma in previous colonoscopy = Risk of advanced colorectal neoplasm according to the number of adenoma in previous colonoscopy

다국어 초록 (Multilingual Abstract)

Background: There is controversy about the follow-up period of colonoscopy according to the number of adenoma at index colonoscopy. The aim of this study is to determine the appropriate interval time of surveillance study according to the number of adenoma at index colonoscopy by comparing the cumulative incidence of advanced adenoma or overall adenoma during follow-up period. Methods: We reviewed retrospectively the health records of 982 patients who underwent colonoscopic polypectomy from 2011 to 2012 and follow-up colonoscopy after 2.5 or more years from index colonoscopy. The patients were grouped into 1-2 adenomas, 3-4 adenomas, 5-9 adenomas. We compared the cumulative incidence of advanced adenoma or overall adenoma during study period. Results: After median follow-up of 47.6 months, 77 (7.8%) patients developed advanced adenoma and 662 (67.4%) patients developed adenoma at follow-up study. Compared with the cumulative incidences of advanced adenoma and overall adenoma, those of 3-year are 0.8% and 1.1% in 1-2 adenomas group, 1.9% and 15.5% in 3-4 adenomas group, 3.7% and 25.5% in 5-9 adenomas group. And those of 5-year are 7.3% and 61.9% in 1-2 adenomas groups, 9.7% and 70.0% in 3-4 adenomas group, 17.5% and 77.0% in 5-9 adenomas group. Conclusions: The cumulative incidence of advanced adenomas does not show meaningful difference after 3 years from index colonoscopy. So it is considered to have 3-year follow-up period rather than 1-year in patients with 3-9 adenomas at index colonoscopy.