Definitive Radiotherapy for Patients With Anal Squamous Cell Carcinoma: A Retrospective Cohort Study.

Background Anal squamous cell carcinoma accounts for less than 2-3% of all digestive system carcinomas. The present study aimed to determine the clinical characteristics, treatment patterns, and treatment outcomes of patients at our institution. Methodology We reviewed the clinical data of all consecutive patients with anal squamous cell carcinoma who were treated with definitive radiotherapy in our department between July 2009 and July 2020. Radiotherapy was delivered in 1.8-2 Gy daily fractions to a whole pelvic dose ranging from 45 to 50 Gy, followed by boost radiotherapy of 10-15 Gy, resulting in a total dose of approximately 60 Gy. Concurrent chemotherapy with radiotherapy included 5-fluorouracil/mitomycin C or 5-fluorouracil/cisplatin. Results A total of 14 patients with a median age of 61.5 years (range: 45-85 years) were analyzed. There were nine women and five men. The clinical T stage was T1 in two patients, T2 in six patients, T3 in two patients, and T4 in four patients. The clinical N stage was N0 in four patients and N1 in 10 patients. Patients with clinical stage III disease comprised 79% of the entire study population. For the entire cohort, the five-year overall survival rate was 83.3% and the five-year progression-free survival rate was 48.5%. One patient experienced grade 3 fecal incontinence, and the others experienced no radiation-induced severe delayed adverse events. Conclusions The results of our study demonstrated that definitive radiotherapy with or without chemotherapy for patients with anal squamous cell carcinoma is an effective and feasible treatment.