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Canadian Journal of Gastroenterology - Volume 4 1990, Issue 4, Pages 174-178

Review Department of Pathology and Medicine, University of Washington, Seattle, Washington, USA

Received 3 March 1989; Accepted 6 March 1990

Copyright © 1990 Hindawi Publishing Corporation. This open-access article is distributed under the terms of the Creative Commons Attribution Non-Commercial License CC BY-NC, which permits reuse, distribution and reproduction of the article, provided that the original work is properly cited and the reuse is restricted to noncommercial purposes.


Cancer of the colon and rectum is the second most commoncancer in men and women in North America. Early diagnosis results in detectionof early stage tumours with a high probability of cure. Several studies documentthe efficacy of screening for the early detection of colorectal cancer; however, its incidence is so high chat screening the entire older adult population is notfeasible. Thus, attempts have been made to focus screening on patients at higherthan average risk for colorectal carcinoma; these include patients with predisposingconditions or premalignant lesions of the colon. Common predisposingconditions include previous resection of an adenoma or carcinoma, a familyhistory of colorectal carcinoma, and ulcerative colitis of more than IO years-duration. The most important premalignant lesion is the colonic adenoma. Suchlesions must be removed in their entirety and examined histologically to excludethe presence of carcinoma. Approximately 51 % of patients with colonicadenomas removed by endoscopic polypectomy will be found to have a carcinomawithin the polyp. If a pedunculated adenoma containing invasive carcinomacan be removed with a clear stalk margin, the risk of nodal metastasis isvery low, probably less than 2%. In contrast, sessile lesions containing carcinomaalready show invasion into the submucosa of the underlying bowel wall with asignificant risk of nodal metastasis. Segmental colonic resection is rarely necessaryfor management of the patient with carcinoma arising in a pedunculatedadenoma, but it is often justified for the patient with carcinoma in a sessile lesion.Dysplasia arising in ulcerative colitis is another important premalignant lesionthat can be detected by colonoscopy with biopsy. The presence of high gradedysplasia in a patient with longstanding ulcerative colitis is an indication forcolectomy.

Autor: Rodger C Haggitt



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