T1-2 anal carcinoma requires elective inguinal radiation treatment – The results of Trans Tasman Radiation Oncology Group study TROG 99.02

Abstract

Background and purpose Elective inguinal irradiation increases morbidity. We describe outcomes of moderate intensity chemoradiation treating anal canal and adjacent pelvic nodes only. Material and methods Forty patients with T1-2, N0 anal carcinoma were enrolled between March 1999 and March 2003. Inguinal nodes were NOT electively irradiated. The anal canal and regional pelvic nodes received 36 Gy/20# over 4 weeks, and 2 weeks later the anal canal was boosted with 14.4 Gy/8#. Chemotherapy was 5 fluorouracil 800 mg/m 2/day on days 1–4 and 36–39, and Mitomycin C 10 mg/m 2 on day 1. Results Median follow-up was 44 months. Complete response was 95%. Four year results were; overall survival 71%, local control 82%, and colostomy-free survival (including salvage) 85%. Inguinal failure occurred in 22.5% but was isolated in only 12.5%. Treatment was well tolerated acutely with no toxic deaths. Severe late toxicity occurred in 7.5%. Conclusions This moderate dose ‘non inguinal’ chemoradiation regimen resulted in modest acute toxicity, minimal long term morbidity and local control in line with other series. However staging failed to identify 12.5% of patients whose isolated inguinal failure might have been prevented by elective irradiation. Without more effective staging, all patients should receive elective inguinal irradiation.