CHARACTERISTICS OF SMALL-BOWEL CARCINOMA IN HEREDITARY NONPOLYPOSIS COLORECTAL-CARCINOMA

BACKGROUND. Small bowel carcinoma is uncommon. However, hereditary non -polyposis colorectal carcinoma (HNPCC) patients are at increased risk of small bowel carcinoma. The purpose of this study was to characteri ze small bowel tumors in HNPCC patients. METHODS. A questionnaire was mailed to the members of International Collaborative Group on HNPCC (I CG-HNPCC) requesting clinicopathologic data in their registries on HNP CC patients with small bowel carcinoma. Survival was estimated utilizi ng the Kaplan-Meier method. RESULTS, Forty-two individuals from 40 HNP CC families developed 42 primary and 7 metachronous small bowel tumors . There were 46 adenocarcinomas and 3 carcinoid tumors. The median age at diagnosis of the index small bowel tumor was 49 years. Mismatch re pair gene mutations were present in 15 of 42 patients (36%). There wer e nine hMLH1 and six hMSH2 mutations. The small bowel was the first si te of carcinoma in 24 patients (57%). The median survival for the 42 p atients was 47 months (range, 0-447 months). The overall 5- and 10-yea r survival rates were 44% and 33%, respectively. CONCLUSIONS. Small bo wel tumors can be the presenting neoplasms in HNPCC patients. Similar to colorectal carcinoma in HNPCC, small bowel adenocarcinomas in HNPCC patients occur at an earlier age and appear to have a better prognosi s than those occurring in the general population. Cancer 1998;83:240-4 . (C) 1998 American Cancer Society.