Results The chief causes of LGB in the eldly we re as follows:rectal or colonic carcinoma (444cases,29.5%),rectal or colonic polyps(363cased,24.1%)and anorectal disease(201cases,13.3%).

• 1507例患者中，检出率最高为结肠癌444例，占29。5%25，其次为结肠息肉363例，占24。1%25，第三为肛管疾病201例，13。3%25及炎症性肠病89例（5。9%25）等。