Colorectal carcinoma and preceding fistula in Crohn's disease

Abstract

BACKGROUND: An increased risk for intestinal carcinoma is known in Crohn's disease, but there are also several reports on patients with perianal fistula and later carcinoma at this location - so to call fistula associated carcinoma. METHODS: We retrospectively investigated 591 patients with CD who underwent abdominal surgery during the last 10 years (1997-2006) and found seven patients (5 male, 2 female, median age: 53 years (range 37-74)) with colorectal cancer (Dukes A-C), four of them (57%) with fistula associated CRC. These seven patients with CRC were matched 1:3 to randomly selected Crohn's patients based on age. The medical records of these 21 patients (11 with perianal fistula (52%)) were evaluated with respect to duration and pattern of intestinal involvement of CD, fistula history, intestinal surgery, perianal surgery, prior immunosuppressive and 5-ASA derivative intake. RESULTS: Colorectal cancer was significantly (p=0.048) associated with longstanding anorectal fistula (median=11 years (range 0-28 years)) in the CRC group compared to the matched Crohn's patients (median=1 year (range 0-6 years)). Earlier colonic surgery seemed to protect from later malignancy (p=0.036). No significant symptoms preceded rectal carcinoma, except for new blood drainage from fistula in 2 patients. Two patients underwent ileocolonoscopy within 1 year before the diagnosis of malignancy and 2 patients underwent MRI of the pelvic region within 4 months. CONCLUSION: Colorectal carcinoma is frequently associated with the presence of longstanding anorectal fistula.