Results and toxicity of the treatment of anal canal carcinoma by radiation therapy or radiation therapy and chemotherapy.

The results of treating anal canal carcinoma by radical external beam radiation alone (RT) or by combined 5-fluorouracil, mitomycin C and radiation (FUMIR), were compared in nonrandomized groups of patients treated in a single center. In each treatment regimen, surgery was reserved for those patients with residual carcinoma. The uncorrected 5-year survival rate in each group was approximately 70%, but primary tumor control was achieved in 93% (28/30) with FUMIR compared to 60% (15/25) treated with RT. Acute hematologic and enterocolic toxicity with uninterrupted external beam radiation courses of 5000 cGy in 4 weeks plus chemotherapy led to the adoption of split-course treatment. Serious late toxicity requiring surgical intervention occurred in 3 of 25 following RT, and in 5 of 30 following FUMIR. Colostomies were needed as part of treatment for residual carcinoma or for the management of treatment-related toxicity in 11 of 25 treated by RT and have been required to date in 4 of 30 treated by FUMIR. The improvement in the primary tumor control rate and the reduction in the number of patients requiring colostomy when compared with the results of RT favor combined chemotherapy and radiation as the initial treatment for anal canal carcinoma.