Adenocarcinoma of the anal canal

Anal adenocarcinoma is a rare tumor, comprising only 3 to 19% of all tumors arising in the anal canal. The site of origin of anal adenocarcinoma is controversial, but likely candidates include the anal glands and chronic fistula-in-ano. Signs and symptoms of anal adenocarcinoma are similar to other benign anorectal conditions, often delaying accurate diagnosis and potentially compromising outcome. The optimal surgical treatment remains to be defined, but abdominoperineal resection appears to be indicated in the majority of cases. Similarly, the role of radiation and chemotherapy remains unclear. Anecdotal reports suggest that mitomycin-based chemoradiation protocols similar to Nigro's protocol for squamous cancer of the anal canal may be efficacious as primary therapy for anal adenocarcinoma. Adjuvant radiation and 5-FU-based chemotherapy similar to rectal cancer protocols, given either preoperatively or postoperatively, may also improve local control and survival following surgical resection. Further studies, however, are needed.