Toxic Effects of Volume-modulated Arc Therapy for Esophageal Squamous Cell Cancer: Preliminary Clinical Results

Abstract

Background/Aim: To evaluate the toxic effects associated with various factors, including the presence or absence of concurrent chemotherapy with volume-modulated arc therapy (VMAT) and dose parameters for esophageal cancer (EC), and to assess the safety and feasibility of the VMAT protocol. Patients and Methods: Patients with EC who received definitive VMAT between December 2016 and December 2020 were retrospectively analyzed. VMAT plans were designed to deliver 60 Gy to the primary tumor, 54 Gy to high-risk sites, and 51.3 Gy to regional lymph node sites. Toxic effects were evaluated for esophagitis, neutropenia, esophageal stricture, pericardial effusion, radiation-associated pneumonia. Results: Forty-five patients received concurrent chemoradiotherapy (CCRT), while 29 were treated with radiation therapy (RT) alone. The following grade 3 complications were detected: Neutropenia in four patients (5.4%), esophagitis in two (2.7%), and esophageal stricture in one (1.4%). Grade 4 or more complications were not observed. The median age of the CCRT group (67 years) was significantly lower than that of the RT-alone group (77 years) (p<0.0001). The incidence of esophagitis was significantly higher in the CCRT group (75.5%) than in the RT group (48.3%) (p=0.033). The univariate analysis identified increasing mean dose to the pericardium as a significant risk factor for pericardial effusion, and CCRT and performance status ≥1 as significant for radiation-associated pneumonia. These factors were not significant in the multivariate analysis. Neutropenia and esophageal stricture were not associated with any factor examined. Conclusion: VMAT alone and in CCRT performed with our protocol was safe and feasible in patients with esophageal squamous cell cancer.