Volumetric modulated arc radiotherapy with concomitant chemotherapy for the anal squamous carcinoma: A Welsh experience

ABSTRACT

Category Outcomes of treatment (including chemotherapy, chemo-RT and RT) Purpose: To describe the five-year treatment outcomes of patients with anal squamous carcinoma treated with concurrent chemoradiotherapy (CRT) specified with volumetric modulated arc radiotherapy (VMAT) at a Welsh tertiary referral centre. Methods and materials A total of 80 anal cancer patients received radical CRT between 2016 and 2021. CRT consisted of 50.4 Gy/28 fractions (1.8 Gy daily) to the gross tumour volumes (GTV), and the elective nodes were prescribed 40 Gy/28 fractions (1.42 Gy/daily) for patients having a cT1/2N0M0. Patients with cT3-T4/N0-N1a-cM0 were prescribed 53.2 Gy/28 fractions (1.9 Gy daily) to the GTV;gross nodal volumes were prescribed 50.4 Gy/28 fractions (1.8 Gy daily) if sized <=3 cm or 53.2 Gy/28 fractions (1.9 Gy daily) if >3 cm;elective nodal areas were given 40 Gy/28 fractions (1.42 Gy daily). Mitomycin and capecitabine were administered concurrently. The primary outcome was colostomy-free survival (CFS). Secondary outcomes were cancer-specific survival (CSS), disease-free survival (DFS), overall survival (OS) and adverse effects. Result(s) Median follow-up was 31.3 months (3-61). The five-year CFS was 94.3% (95% CI 50.0%-96.5%). The five-year CSS, DFS and OS were 92% (95% CI 60.5-95%), 86.7% (95% CI 58-89%) and 67.9% (95% CI 56.6-75.1%) respectively. A total of four (5%) local recurrences and one (1.3%) regional recurrence was observed. A total of seven patients (8.7%) had distant metastasis (liver was a frequent site;57.1%);three patients (3.7%) died of COVID pneumonia. Late toxicities were as vaginal stenosis (6.3%), sexual dysfunction (1.25%) and urine incontinence (1.25%). Second malignancies were as lung (2.5%), gastric (1.3%), pancreatic cancer (1.3%) and cholangiocarcinoma (1.3%). Conclusion(s) Our experience supports the use of VMAT on a routine basis for the CRT of anal squamous cell carcinoma. Copyright © 2022