Abstract

Background
/Aims: Because detection and removal of colonic adenoma provided an opportunity to prevent colorectal cancer, advanced adenoma (＞10 mm, villous or high grade dysplasia) should be the major target of screening. In this study, we assessed the diagnostic sensitivity of one- or two-time immunochemical fecal occult blood test (i-FOBT), flexible sigmoidoscopy and their combination in patients with advanced adenoma or non-advanced adenoma. Methods: From January to October 2002, we performed colonoscopy with i-FOBT using latex agglutination method in 879 individuals. Among these, we diagnosed 234 polyps in 93 patients with advanced adenoma and 179 polyps in 109 patients with non-advanced adenoma. After the diagnosis of adenoma, second i-FOBT was done before polypectomy. Based on these data, we evaluated the diagnostic sensitivities of i-FOBT, flexible sigmoidoscopy and their combination for patients with advanced adenoma or non-advanced adenoma. Results: The diagnostic sensitivity of one- or two-time i-FOBT, flexible sigmoidoscopy and flexible sigmoidoscopy with two-time i-FOBT in patients with advanced adenoma vs.non-advanced adenoma were 17.2% vs. 18.3%, 28.0% vs. 29.4%, 70.1% vs. 66.1% and 81.7% vs. 78.0%. Although repeated application of i-FOBT enhanced diagnostic sensitivity for colon adenoma, this test or combination with flexible sigmoidoscopy did not differentiate advanced adenoma from non-advanced adenoma. Conclusions: Although it fails to detect one fifth of colon adenoma, combined two-time i-FOBT testing with flexible sigmoidoscopy is an effective and feasible screening modality for advanced colon adenoma. (Korean J Gastrointest Endosc 2004;28:291⁣297)

• Keywords: Advanced colon adenoma, Sigmoidoscopy, Fecal occult blood test, Screening