Conservative treatment by irradiation of epidermoid carcinomas of the anal margin

Few series have described treatment results of anal margin tumors as defined in the UICC 87 classification. The purpose of this article is to describe experience with an uncommon condition in a single cancer center.

From 1971 to 1995, 32 patients with carcinoma of the anal margin were irradiated with a curative intent, and 31 were followed-up for more than 6 months (mean = 4.5 years). There were 9 T1, 15 T2, 7 T3, and 1 T4 (vulvar), with 26 N0 and 6 N1. There was a minor invasion of the lower canal in 17 patients. The histological types were 24 squamous cell and 7 basocellular carcinomas, and 1 Paget's disease. The treatment was a combined External Beam Irradiation (EBI) and Brachytherapy (BT) in 16 patients, an exclusive BT in 12 patients, and an exclusive EBI in 4 patients. No prophylactic inguinal irradiation was delivered.

The 5-year actuarial results are as follows: overall survival = 67%, specific survival = 89%. The only prognostic factor was nodal involvement (p < 0.001). T-stage, T-size, age, sex, and treatment schedule were not significant. The overall local control was 77%, and 93.5% after salvage. Two N0 patients relapsed in inguinal areas (one was salvaged). Twenty-six percent presented a Grade 3 or 4 late complication, necessitating a temporary colostomy in only one patient. The sphincter conservation reached 84% for the whole series, 80% for patients followed-up 5 years or more, and 89% for cured patients.

Results are similar to other series, and seem better than for anal canal cancer. We recommend exclusive irradiation. There is no data recommending concomitant chemotherapy. Depending on the tumor size and localization, the tumor boost can be applied by EBI or BT. Surgery is reserved for small tumors far from the canal or for salvage. An inguinal prophylactic bilateral irradiation should be recommended for N0, with tumors over 4 cm.