Radiochemotherapy in the conservative treatment of anal canal carcinoma: retrospective analysis of results and radiation dose effectiveness

Abstract

Purpose: This retrospective analysis reports the results on patients with anal canal carcinoma treated by combined radiotherapy and chemotherapy.

Methods and materials: Between March 1993 and December 2001, 43 patients with anal canal carcinoma were treated with radiochemotherapy at the Hospital do Cancer A.C. Camargo. Stage distribution was as follows: I, 3 (7%); II, 23 (53.5%); IIIA, 8 (18.6%); and IIIB, 9 (21%). The median age was 56 years (range, 36-77 years) with most patients being women (4:1). External radiotherapy (RT) was delivered at the whole pelvis followed by a boost at the primary tumor. The median dose of RT at the whole pelvis and at the primary tumor was 45 Gy and 55 Gy, respectively. Chemotherapy was carried out during the first and last 4 days of RT with continuous infusion of 5-fluorouracil (1000 mg/m(2)) and bolus mitomycin C (10 mg/m(2)). Median overall treatment time was 51 days (range, 30-129 days). Thirty-four patients (79%) did not receive elective RT at the inguinal region. Patient's age, tumor stage, overall treatment time, and RT dose at primary tumor were variables analyzed for survival and local control.

Results: Median follow-up time was 42 months (range, 4-116 months). Overall survival and colostomy-free survival at 5 years was 68% and 52%, respectively. Overall survival according to clinical stage was as follows: I, 100%; II, 82%; IIIA, 73%; and IIIB, 18% (p = 0.0049). Complete response was observed in 40 patients (93%). Local recurrence occurred in 9 (21%) patients, and of these, 6 were rescued by surgery. Local control with a preserved sphincter was observed in 34 patients (79%). According to the RT dose, local control was higher among patients who received more than 50 Gy at primary tumor (86.5% vs. 34%, p = 0.012). Inguinal failure was observed in 5 patients (15%) who did not receive inguinal elective RT. Distant metastasis was observed in 11 patients (25.6%). Temporary interruption of the treatment as a result of acute toxicity was necessary in 12 patients (28%). Four patients developed mild chronic complications.

Conclusions: This analysis suggests that the treatment scheme employed was effective for anal sphincter preservation and local control; however, the incidence of distant metastases was relatively high. The clinical stage was the main prognostic factor for overall survival. Local control was higher in patients treated with doses of more than 50 Gy at primary tumor. The high incidence of inguinal failure implies the need for elective RT in this region.