Primary radiation therapy in the treatment of anal carcinoma.

From 1966 to 1981, 47 patients with a diagnosis of anal carcinoma were irradiated. This group was composed of 23 males and 24 females, with age ranging from 38-84 years (average 64.4 years). The average age of the males was eight years less than the females. Of the 47 patients, 39 had an intact anal canal following biopsy and were treated with curative intent. Thirty-one of these 39 had no evidence of nodal metastasis (N0) and eight had groin, pelvic and/or para-aortic nodal disease. Only three patients were treated with pre-irradiation chemotherapy; all had locally advanced disease. Five patients were treated preoperatively and 34 were treated definitively with cancericidal doses of irradiation. Acute radiation reactions requiring a rest-break were noted in 28% of patients, but all were managed as outpatients without untoward chronic sequelae. Chronic complications were noted in 13 patients, including two patients who required colostomy for severe anal stenosis and two who required A-P resection for large painful ulcers. Two of these four patients had received part of their treatment with an interstitial implant and one had an excessively high dose of perineal irradiation. Twenty-eight of 35 patients (80%) treated with irradiation alone have remained locally controlled without further treatment. An additional four have been salvaged by surgery. Only three patients had interstitial implants as part of their treatment course. Actuarial survival at five years for the N0 patients and the group as a whole are 95.6 and 79.3%, respectively. It is concluded that external beam irradiation alone, properly fractionated to cancericidal doses, can control anal carcinoma with acceptable morbidity rates and without the use of either chemotherapy or interstitial implants in most cases. There is also a strong correlation suggesting that anal intercourse and male homosexuality play a significant role in the etiology of this disease.