Screening for Hereditary Non-polyposis Colorectal Cancer in the Netherlands

Abstract

Hereditary non-polyposis colorectal cancer (HNPCC) is usually subdivided into two main categories: hereditary site-specific colorectal cancer (Lynch syndrome I) and colorectal cancer in association with other forms of cancer (Lynch syndrome II). Identification of HNPCC is a basis for secondary prevention. The objectives of our study were (1) to assess the value of screening; (2) to investigate the natural history; and (3) the hereditary tumor spectrum in HNPCC. Screening was performed in 24 families (colonoscopy or double-contrast barium enema and sigmoidoscopy). The patients were subdivided into two groups. Group A comprised patients with colorectal cancer who were referred because they were symptomatic. Group B included family members of these patients who were found to have a colorectal lesion by screening. We compared these groups with respect to the stage of tumor growth. Histological examination of the tumors in group A (97 patients) revealed Dukes A carcinomas in six patients, Dukes B carcinomas in 43, Dukes C carcinomas in 24 and Dukes D carcinomas in 11 patients (classification unknown in 13 patients). In group B (20 patients) adenoma was found in 14 and carcinoma in six patients (Dukes A in two and Dukes B in four patients). A total of 103 patients, including those whose tumors were detected by screening, had a colorectal carcinoma. The age at diagnosis ranged from 24 to 81 years (mean age: 46 years). The localization of the colonic tumors was proximal in 60%. Multiple primary tumors were found in 25%. Sixty-five extra-colonic tumors were found: endometrial cancer in 16 patients belonging to 12 families, cancer of the stomach in ten patients representing five families, urinary-tract tumors in eight patients from four families and many other tumors less frequently. The results suggest that screening leads to the early detection of colorectal carcinomas and adenomas in asymptomatic members of HNPCC-families. Screening should be initiated at the age of 20 and continued during the life of the individual. Careful examination of the right colon is indicated because of the frequent occurrence of tumors in the proximal colon. A subtotal colectomy is indicated at the time of diagnosis of the initial colon cancer, because of the risk of multiple primary tumors. Carcinoma of the endometrium, stomach and urinary tract appear to belong to the hereditary tumor spectrum.