Fistula-associated anal adenocarcinoma: good results with aggressive therapy.

PURPOSE: To evaluate the clinical features, pathology, treatment, and outcome of patients with fistula-associated anal adenocarcinoma.

METHODS: We identified 14 patients with histologically proven fistula-associated anal adenocarcinoma. We reviewed their medical records and pathology specimens to characterize their presentation, treatment, and clinical outcome.

RESULTS: Nine patients presented with a persistent fistula, 3 with a perianal mass, 1 with pain and drainage, and 1 with a recurrent perianal abscess. The average age at time of diagnosis was 59 (range, 37-76) years. Eleven patients had preexisting chronic anal fistulas. Ten had Crohn's disease, and 1 had previously received pelvic radiation therapy. The diagnosis of cancer was suspected during physical examination in 6 of the 14 patients (43 percent). Twelve patients had extensive local disease at presentation. Primary abdominoperineal resection was performed in 11 patients, 7 following neoadjuvant chemoradiation. Six patients received postoperative chemotherapy, and 2 received postoperative radiation. Four patients died with metastatic disease. The remaining 10 patients are alive without evidence of disease at a mean follow-up of 64.3 (range, 14-149) months.

CONCLUSIONS: The diagnosis of fistula-associated anal adenocarcinoma is often unsuspected. Most patients can be cured with aggressive surgical and adjuvant chemoradiotherapy.