The incidence of bowel cancer was studied in 132 patients who had undergone bypass surgery for Crohn's disease and who had been admitted to The Mount Sinai Hospital between 1960 and 1976. Seven patients (5.3 per cent) developed cancer (4 of 63 with ileocolitis and 3 of 69 with ileitis). All seven cancers appeared in excluded loops, four in small bowel and three in colon. Six of the cancers occurred at sites of previous active inflammatory disease and one in a relatively normal "skipped" area of cecum. Four were associated with fistulas: two with enterovesical; one with enterocutaneous; and one with both. In only one case was a tumor mass palpable. All seven patients in this series underwent operation and all showed metastatic spread to liver, lymph nodes, or adjacent organs. All patients died within two years of the diagnostic laparotomy. The mean latent period between onset of disease and appearance of cancer was twenty-seven years, and between bypass surgery and appearance of cancer thirteen years. Four of the seven cancers occurred relatively early, within four years of the bypass procedure, but all seven cases had one feature in common-a long duration of Crohn's disease prior to the development of cancer, ranging from seventeen to forty-four years. The diagnosis of cancer in excluded bowel was difficult to make and impossible to confirm prior to laparotomy. Among the large bowel cancers, a preoperative diagnosis was established, by sigmoidoscopy, in only one case. Cancer in a bypassed loop should be suspected in any case of Crohn's disease of long duration when a late recrudescence of symptoms occurs, especially when the symptoms are associated with the new appearance of fistula or mass. © 1978.
Greenstein, A. J., Sachar, D., Pucillo, A., Kreel, I., Geller, S., Janowitz, H. D., & Aufses, A. (1978). Cancer in Crohn’s disease after diversionary surgery. A report of seven carcinomas occurring in excluded bowel. The American Journal of Surgery, 135(1), 86–90. https://doi.org/10.1016/0002-9610(78)90015-6