Fistula-Associated Anorectal Cancer in the Setting of Crohn's Disease

BACKGROUND: Cancer arising from perianal fistulas in patients with Crohn's disease is rare. There are only a small series of articles that describe sporadic cases of perianal cancer in Crohn's disease fistulas. Therefore, there are no clear guidelines on how to appropriately screen patients at risk and choose proper management. OBJECTIVE: The purpose of this study was to describe patients diagnosed with cancer in perianal fistulas in the setting of Crohn's disease. DESIGN: The study involved an institutional review board-approved retrospective review of medical charts of patients with perianal Crohn's disease. The data extracted from patient charts included demographic and clinical characteristics. SETTINGS: Patients seen at the Mount Sinai Medical Center were included. PATIENTS: We identified patients who were diagnosed with perianal cancer in biopsies of fistula tracts. MAIN OUTCOME MEASURES: We observed the number of patients with Crohn's disease who had fistulas, cancer in fistula tract, and time to diagnosis. RESULTS: The charts of 2382 patients with fistulizing perianal Crohn's disease were reviewed. Cancer in a fistula tract was diagnosed in 19 (0.79%) of these patients, 9 with squamous-cell carcinoma and 10 with adenocarcinoma. The majority of the 19 patients (68%) had symptoms typical of perianal fistula. The mean time from diagnosis of Crohn's disease to fistula diagnosis and from fistula diagnosis to cancer diagnosis was 19.4 and 6.0 years. In 5 patients (26%), cancer was not diagnosed in the first biopsy obtained from the fistula tract. LIMITATIONS: This is a retrospective chart review of a rare outcome; the results may not be generalizable. CONCLUSIONS: Routine biopsies of long-standing fistula tracts in patients with Crohn's disease should be strongly considered and may yield an earlier diagnosis of cancer in the fistula tracts.