Contribution of conformal therapy in the treatment of anal canal carcinoma with combined chemotherapy and radiotherapy: results of a phase II study.

Abstract

To evaluate the feasibility of delivering conformal radiotherapy (RT) and concurrent chemotherapy without a mandatory break in patients with anal canal carcinoma. Thirty patients with T2-T4 tumors were treated with a combination of 54 Gy in 30 fractions and two cycles of 5-fluorouracil and mitomycin C. Dose-volume histograms were obtained for bone marrow, small bowel, and skin to compare the conventional technique using the Radiation Therapy Oncology Group standard with our conformal technique. The mean dose ratio of the conventional compared with the conformal technique for bone marrow, small bowel, and skin was, respectively, 2.1-2.7, 3.0, and 2.0, in favor of the conformal technique. All patients completed their treatment without a treatment break. An incidence of Grade 3 toxicity for bone marrow, bowel, and skin of 13.3%, 3.3%, and 20%, respectively, was observed. With a median follow-up of 33 months, a 4-year local recurrence-free survival rate of 91% was observed. The results of this study have shown that conformal RT leads to a well-tolerated treatment. The treatment time is shortened to 6 weeks. A significant decrease in the acute toxicity rate suggests that by decreasing the "volume factor," conformal RT improves the therapeutic index in patients treated with combined chemotherapy and RT.