Purpose: This is a retrospective review of all anorectal cancers arising in patients with Crohn's disease (CD).
Methods: In an effort to update our previously reported experience with carcinomas arising in anorectal fistulas in CD, data from 1999 to the present was reviewed. Ten perineal cancers were identified and demographic, clinical and pathologic features were analyzed.
Results: Mean age at cancer diagnosis was 43 (range 35-57) and mean duration of Crohn's disease was 28.7 years (range 22-38). Ten anorectal cancers were diagnosed in 8 males and 2 females. There were 9 adenocarcinomas and 1 anal squamous cell carcinoma. In 2 patients, anorectal caners were associated with synchronous colon adenocarcinomas. One tumor was classified as stage I (11.1%), 6 as stage II (66.7%), and 2 as stage IV (22.2%). In all 10 patients, cancer was diagnosed on biopsy of perianal fistulas or suspicious lesions in proximity to chronic fistulas while in 2 patients, cancers were diagnosed endoscopically in patients with perianal disease. Medical management of CD in those patients consisted of no medications (1), steroids (6), 5-ASA (4) and immune modulators including cyclosporine, 6MP, remicade and imuran (6) alone or in combination. In this series, 4 patients had undergone prior segmental or subtotal colon resection and 4 were diverted at the time of cancer diagnosis for severe perianal disease. Detailed pathologic examination of the mucosa adjacent to cancers was available in 8/10 patients. Rectal dysplasia was identified in 4/8 patients (50%) and a background of active chronic proctitis ranging from mild to severe was noted in 5/8 (62.5%). Treatment modalities consisted of neoadjuvant therapy followed by abdominoperineal resection (APR) in 2/10, or by total proctocolectomy (TPC) in 2/10, TPC (1), APR (4) or ongoing neoadjuvant in 1 patient. In the 2 patients with stage IV disease, proctectomy was delayed by 5 months in one patient with known colonic high-grade dysplasia and by more than one year in the other with severe perianal disease in the setting of long-standing CD due to patient non-compliance.
Conclusions: In this series, all anorectal carcinomas arising in patients with Crohn's disease were associated with severe perianal fistulizing disease, and the majority arose in the immediate vicinity of the fistulas. Aggressive endoscopic and open anorectal biopsies in patients with long-standing Crohn's disease with perianal fistulas may result in the diagnosis of anorectal carcinoma at a relatively early stage.