Objective: To report the risk of metachronous colorectal neoplasia after colectomy for cancer in Hereditary Nonpolyposis Colorectal Cancer (HNPCC) syndrome.
Summary background data: Patients meeting Amsterdam criteria for diagnosis of HNPCC have a lifetime colorectal cancer risk approaching 80%, and a metachronous cancer rate of approximately 25%. Therefore, when colon cancer is diagnosed, total rather than segmental colectomy is advocated. However, information about adenoma and carcinoma risk after index surgery is still underreported.
Methods: A hereditary colorectal cancer database was reviewed for patients meeting Amsterdam criteria who underwent colectomy for cancer. Patient demographics, surgical management, and results of follow-up were recorded. Metachronous colorectal adenoma and carcinoma development were the primary end points.
Results: A total of 296 patients (253 with segmental colectomy and 43 with total colectomy/ileorectal anastomosis) were analyzed. Of the 253 segmental colectomy patients, 221 (88%) had postoperative endoscopic surveillance with median follow-up of 104 months. In 74 patients (33%), 256 adenomas were detected, including 140 high-risk adenomas in 48 patients (22%). Fifty-five patients (25%) developed a second colorectal cancer at a median of 69 months after index surgery. Stages of the metachronous cancers were I-16, II-18, III-12, and IV-2. By comparison, 4 of 38 patients (11%) who underwent total colectomy developed subsequent high-risk adenomas and 3 (8%) developed metachronous cancer.
Conclusions: Amsterdam patients undergoing partial colectomy have a high rate of metachronous high-risk adenomas and carcinomas. Total colectomy for the index cancer is the procedure of choice. For either surgical option, yearly endoscopic surveillance is essential to remove premalignant adenomas.