P-240 Anal cancer treatment: Major reduction of acute toxicity with an approach using 4-fractions-per-week

Abstract

The purpose of our study was to report the long-term excellent outcome in patients with squamous cell carcinoma of the anal canal (SCCA), who were treated with definitive chemo-radiotherapy (CRT) using an innovative approach of 4-fraction-per-week and conventional 3D radiotherapy technique. Twenty-four patients who received definitive chemo-radiotherapy from January 2013 to December 2018 were included in this study. All patients received 5-fluorouracil with mitomycin C as this has been our institutional practice. No patients received cisplatin. All 24 patients were treated with conventional radiotherapy technique. The median dose was 5400 cGy (range = 5220-5580 cGy). Median follow-up was 36 months. All 24 patients were treated using a modified regimen of 5 fractions only for the first week, followed by 4 fractions per week thereafter (Fridays off starting the second week of treatment with no planned break). For a few patients receiving the highest dose of 5580 cGy in 31 fractions, this was equivalent to 7.5 weeks or 51 days. Acute skin toxicity was: grade I: 21 patients (88%), grade II: 3 patients (12%), with no grade III or IV skin toxicity. Acute hematologic toxicity: grade I: 16 patients (66%), grade II: 7 patients (29%), with no grade III or IV hematologic toxicity. Acute GI toxicity: grade I: 14 patients (58%), no grade II, III or IV GI toxicity. All patients completed treatment as prescribed. Treatment compliance was 100%. No patients required hospitalization from side effects of chemo-radiotherapy treatment. This innovative approach of 4-fraction-per-week using conventional 3D radiotherapy technique was initially conceived to reduce skin toxicity. Interestingly, in addition to a significant reduction of acute skin toxicity, hematologic, and GI toxicity was also greatly reduced, with virtually no need for treatment breaks, and yielded excellent local-regional control and overall survival when compared with known randomized RTOG studies. This innovative approach of 4-fraction-per-week deserves further study by individual investigators and/or appropriate clinical trials.