Adenocarcinoma in regional enteritis of the small intestine.

An increased risk for regional enteritis patients of small bowel adenocarcinoma to develop has been suspected but unproved. We have analyzed 49 cases reported since 1957 and two additional ones of our own. These have been compared with a current group of small bowel adenocarcinomas not associated with regional enteritis. The Crohn-associated cancers differed from adenocarcinomas not associated with Crohn disease in that (1) mean age at cancer discovery was less (46 vs 64 years), (2) more cancers arose in the ileum (76% vs 27%), (3) diagnosis and cure were less successful, and (4) they occurred more frequently. The 32 cases reported in the past five years were compared with the expected 0.1 to 5 cases. Regional enteritis patients were found to have an increased risk for the development not only of small bowel adenocarcinoma, but one that is more occult and lethal than that in individuals wihtout Crohn disease.