Fistula-associated anal adenocarcinoma in Crohn's disease

Adenocarcinoma arising from perianal fistulae in patients with Crohn's disease (CD) is rare. The literature consists mainly of case reports and small series making characterization of this clinical entity difficult. We present 6 patients with CD and fistula-associated anal adenocarcinoma (FAAA) and a systematic review of published series.

Retrospective charts were reviewed of 6 consecutive patients with FAAA in CD treated from 1992 through 2007. All available variables of our patients and of all available published cases were included for statistical analysis.

All patients treated at our institution had severe perianal CD at presentation. The average age at time of diagnosis was 45.5 years. All patients underwent abdominoperineal resection (APR) and 4 received chemoradiation. Four patients died with metastatic disease, 1 is alive with pelvic recurrence at 55 months, and 1 is alive without evidence of disease at 19 months follow-up. A total of 23 publications including 65 patients (37 female, mean age 53 years) with FAAA were reviewed in our systematic review. The average fistula duration was 14 years. Mean delay of cancer diagnosis was 11 months. APR was performed in 56 patients with an overall 3-year survival rate of 54%. Thirteen of 15 patients with node-positive tumors died with recurrent disease following surgery.

Adenocarcinoma arising from long-standing perianal CD fistulae is being increasingly reported. The outcome is poor following operative treatment, especially if perirectal lymph nodes are involved. Periodical cancer surveillance should be performed in all patients with long-standing perianal CD fistulae.