Small bowel cancer in western Canada.

Based on incident cases of small intestinal cancers in the four western Canadian provinces reported in the population-based cancer registries of British Columbia, Alberta, Saskatchewan and Manitoba we evaluated the descriptive epidemiological characteristics such as age, sex and subsite distribution of adenocarcinomas, carcinoids, lymphomas and sarcomas for the period 1975-1989. The distribution of adenocarcinomas, carcinoids and lymphomas presented a clear trend along the length of the small bowel. Most of the adenocarcinomas (54.7%) occurred in the duodenum and their relative frequency decreased in aboral direction: 29.9% in the jejunum and 16.0% in the ileum. The carcinoids showed an opposite trend, an increasing relative frequency in aboral direction: 3.9% in the duodenum, 9.2% in the jejunum and 86.7% in the ileum. Lymphomas were more frequent in the ileum (49.5%) compared to jejunum (29.4%) and duodenum (21.0%). Most sarcomas occurred along the jejunum (46.7%). The mean and median ages of lymphoma and sarcoma patients were significantly lower compared to adenocarcinoma and carcinoid cases. There was no difference in mean and median age by gender in the adenocarcinoma and carcinoid categories, but in the lymphoma and sarcoma groups males were significantly younger than females.