Adenocarcinoma and lymphoma of the small intestine. Distribution and etiologic associations.

Malignant small-bowel tumors in 171 patients over 64 years included 68 with adenocarcinomas, 41 with primary lymphomas, 50 with carcinoids, and 12 with sarcomas. The distribution of the carcinomas showed approximately 80% preponderance in the duodenum and proximal jejunum. A similar distribution in the upper small bowel in small-bowel carcinomas induced in Fischer and Sprague-Dawley rats by azoxymethane (90-160 mg/kg) suggests defense mechanisms within ileal mucosa. The clinical series from 1958 to 1976 included two Crohn's carcinomas (jejunum, defunctioned ileum), two jejunal cancers (lymphoma, carcinoma) associated with celiac disease, two duodenal carcinomas arising in villous adenomas, and one jejunal lymphoma following exposure to irradiation. Multiple primary malignancies were found in 20 to 25% of enteric cancers. Hemorrhage was more common with carcinoma than lymphoma, but lymphomas predominated considering perforation or a palpable mass. Both carcinoma and lymphoma had 75 to 80% resectability rates and 14 to 15% five-year postoperative survival rates. The prognosis was least poor for carcinoma of the jejunum, one third of patients with "curative" resections surviving five years.