Malignancy in Crohn's disease.

The incidence of cancer in Crohn's disease has been evaluated in 473 patients admitted to Rigshospitalet during the period 1 April 1964 to 1 January 1983. The patients' condition at the end of the survey, their survival, and the number and location of cancers were registered. During the survey period 23 cancers (4.9%) were found. Five were intestinal (1.1%) and were split evenly among the two sexes, whereas among 18 patients with extraintestinal cancers there was only 1 man. There was no increased risk of developing cancer inside the gastrointestinal tract compared with a background population matched for age, sex, and calendar time. Extraintestinal cancer in women was, however, significantly in excess.