Anal Cancer Treatment: Significant Reduction of Acute Toxicity Using 4-Fraction-per-Week Approach

Abstract

The purpose of this study was to compare outcomes in patients with squamous cell carcinoma of the anal canal (SCCA) who were treated with definitive chemo-radiotherapy (CRT) using an alternative approach of 4-fraction-per-week conventional 3D radiotherapy technique. Twenty patients who received definitive chemo-radiotherapy from January 2013 to December 2017 were included in this study. All 20 patients received 5-fluorouracil with mitomycin C (n = 20) as this is our institutional practice, no patients received cisplatin. All 20 patients were treated with conventional radiotherapy technique. The median dose was 5400 cGy (range 5220-5580 cGy). Median follow-up was 24 months. All 20 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 second week of treatment with no planned break). For the highest dose of 5580 cGy in 31 fractions, this is equivalent to 7.5 weeks or 51 days. Acute skin toxicity was: grade I: 18 patients (90%), grade II: 2 patients (10%), with no grade III or IV skin toxicity. Acute hematologic toxicity: grade I: 14 patients (70%), grade II: 6 patients (30%), with no grade III or IV hematologic toxicity. Acute GI toxicity: grade I: 12 patients (60%), no grade II, III, or IV skin toxicity. No patients required hospitalization from side effects of chemo-radiotherapy treatment. All patients completed treatment as prescribed. Treatment compliance was 100%. The 2-year overall survival in this study is 100%. Since this study was conceived for the purpose of reducing skin toxicity, we were pleasantly surprised to also discover that by having Fridays off, the hematologic and GI toxicity profile was mostly minor in nature and was easily manageable. This innovative approach of 4-fraction-per-week using conventional 3D radiotherapy technique was associated with significantly less acute toxicity (skin, hematologic, and GI), with virtually no need for treatment breaks, and yielded excellent loco-regional control, overall survival when compared with known randomized studies. The acute toxicity profile using this regimen of 4-fraction-per-week 3D conformal technique is better than those reported by similar IMRT studies. This innovative approach of 4-fraction-per-week 3D conformal technique deserves further study by individual investigators or by appropriate clinical trials.