Evaluation of a 36 Gy elective node irradiation dose in anal cancer

Abstract Purpose To retrospectively analyze the efficacy of 36Gy of elective node irradiation and report patterns of recurrence in patients with anal cancer treated by chemoradiation with the same radiotherapy (RT) treatment scheme. Methods and materials Between January1996 and December 2013, 142 patients with anal squamous cell cancer were scheduled to receive a dose of 36Gy of elective node irradiation (ENI) to the inguinal area and whole pelvis over 4weeks followed after a 2-week gap by a boost dose of 23.4Gy over 17days to the macroscopic disease. Mitomycin C combined with fluorouracil, capecitabin or cisplatin was given at day 1 of each sequence of RT. Results Disease stages were I: 3, II: 78, III A : 23, III B : 38. Compliance rates were 97.2% with RT and 87.9% with chemotherapy. After a median follow up of 48months [3.6–192], estimated 5-year overall survival and colostomy-free survival were 75.4% and 85.3% respectively. Eleven patients (7.7%) never achieved a complete response, 15 had a local component of recurrence and 5 a regional one. One patient had failure in the common iliac node area outside the treatment fields. The inguinal control rate was 98.5%. The 5-year tumor and nodal control rates were 81.5% and 96.0%, respectively. Conclusion Chemoradiation with a dose of 36Gy ENI achieved excellent nodal control. However, it is necessary to improve the 5-year control rate of the primary tumor. Omitting the gap and using additional doses per fraction or hyper-fractionation are to be explored.