A twenty-year experience with adenocarcinoma of the anal canal

Adenocarcinoma of the anal canal is a rare malignancy with limited data regarding treatment and outcomes. The purpose of this study is to evaluate disease control and survival outcomes in patients with adenocarcinoma of the anal canal.

A retrospective consecutive cohort study of all patients in whom adenocarcinoma of the anal canal was diagnosed between 1983 and 2004 was performed. Tumor, patient, and treatment characteristics were categorized. Overall survival and recurrence outcomes were evaluated by use of the Kaplan-Meier method and the log-rank test. Cox proportional hazards regression analysis was performed to evaluate covariate adjusted effects.

Thirty-four patients were identified; six underwent palliative treatment (Stage IV, n = 4; poor performance, n = 2). Median follow-up for the remaining 28 patients was 37 months (interquartile range, 22-62 months). Thirteen patients (46%) were treated with local excision followed by radiotherapy or chemoradiotherapy. Fifteen patients (54%) underwent radical surgery and preoperative or postoperative chemoradiotherapy. Median disease-free survival was 13 months after local excision and 32 months after radical surgery (P = 0.055). Overall survival at five years was 43% for patients treated with local excision and 63% for patients treated with radical surgery (P = 0.3). Tumor grade was predictive of overall survival (P = 0.04) and recurrence (P = 0.046). On multivariate analysis, the type of surgical treatment was an important predictor of overall survival (P = 0.045) and disease-free survival (P = 0.004).

Combined modality treatment with radical surgical resection improves survival among patients with adenocarcinoma of the anal canal, but a high risk for distant failure emphasizes the need for effective adjuvant therapeutic regimens.