Natural history of minute sessile colonic adenomas based on radiographic findings

Abstract

PURPOSE: With the development of colonoscopy and double-contrast barium enema, detection of minute sessile coIonic adenomas has increased. We evaluated progression of these lesions radiologically and attempted to clarify the natural history. METHODS: A total of 125 minute sessile adenomas (≤5 mm in size) with histologic confirmation were examined by double-contrast barium enema at an interval of more than one year. The average follow-up period was 24 (range, 12–36; standard deviation, 9–4) months. To allow for differences in magnification, adenomas increasing in size by 2 mm or more were defined as growing, and the other lesions were defined as unchanged. RESULTS: Eighty-six adenomas showed no interval change in size. Four adenomas decreased 1 mm in size, and 27 adenomas increased 1 mm in size. The remaining eight adenomas (6 percent) increased by 2 or 3 mm in size. None of the adenomas showed any morphologic changes. There was also no difference in degree of histologic atypia between growing and unchanged adenomas. None of the adenomas developed into carcinomas during the follow-up period. CONCLUSIONS: These data show that most minute sessile adenomas remain unchanged in size and morphology over the long term. Accordingly, these adenomas probably should be followed up radiologically or endoscopically to avoid excessive polypectomy.