title: Impact of adenoma size in distal colon on risk for advanced adenoma of the proximal colon.
abstract: Adenomas of the rectosigmoid colon are considered markers of risk for advanced adenomas of the proximal colon. However, studies report a wide variation in risk. This study was designed to determine the risk for advanced adenomas in the proximal colon in patients from a large, homogeneous population with an advanced or nonadvanced adenoma of the distal colon. We designed a prospective study of 7157 patients who were evaluated for neoplasia by flexible sigmoidoscopy and, when adenomas were found, by colonoscopy. Adenomas were considered advanced if they were > or =10 mm in size or had villous or dysplastic features. Ninety-seven patients had an advanced adenoma of the distal colon (Group A) and were compared with 183 patients who had a nonadvanced adenoma (Group B). Seven patients (7.2%) in Group A had an advanced adenoma of the proximal colon, compared with four patients (2.2%) in Group B (P < 0.05, relative risk = 3.3). When patients with adenomas of the distal colon >5 mm (Group C) were compared to patients with adenomas < or =5 mm (Group D), the prevalence of advanced adenomas of the proximal colon remained at 7% (10/143) for Group C but fell to 0.73% (1/137) for Group D (P = 0.011, relative risk = 9.6). By expanding the criteria for risk from adenomas of the distal colon to include all adenomas >5 mm, the relative risk for advanced adenoma of the proximal colon was increased threefold.
authors.affiliation: Division of Gastroenterology, The Scripps Research Institute, 10666 North Torrey Pines Road, 203N, La Jolla, California 92037, USA. wstrum@scrippsclinic.com
authors.forename: Williamson B
authors.initials: WB
authors.lastname: Strum
mesh_terms: D000236:Adenoma / Q000473:pathology*; D000368:Aged; D003110:Colonic Neoplasms / Q000473:pathology*; D003113:Colonoscopy; D005260:Female; D005629:Frozen Sections; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D018570:Risk Assessment