Clinical outcomes and prognostic factors of volumetric modulated arc therapy (VMAT) of esophageal cancer.

Background: The objective was to evaluate the efficacy and safety of radiotherapy and the prognostic factors in patients with esophageal cancer who received definitive radiotherapy, using volumetric modulated arc therapy (VMAT).

Materials and methods: Forty-seven patients who received definitive radiotherapy using VMAT between September 2017 and December 2020 were enrolled. Prescription doses were 60 Gy in 30 fractions to the planning target volume (PTV) primary and 48 Gy in 30 fractions to the PTV subclinical. Overall survival (OS), progression free survival (PFS), and toxicity were analyzed, and univariate and multivariate analyses were used to investigate the prognostic factors.

Results: Median follow up time was 10 months. Most of the patients had an advanced disease stage (stage I, 12.8%; II, 8.5%; III, 27.7%; IV, 51.0%) patients (38.3%) had a T4 tumor. The median survival time was 14 months (range: 0-56 months). The 2-year OS and PFS were 31.3% and 20.4%, respectively. Acute adverse events (≥ Grade 3) were observed in 25 patients (53.2%), and the most frequent types were dysphagia, hematological toxicities including leukopenia, and febrile neutropenia in 14 (29.8%), 10 (21%), and 10 (21%) patients, respectively. Late adverse events (Grade 3 or higher) were observed in eight patients (17.0%), and the most frequent types were pneumonitis in four patients (8.5%), and Grade 5 in one patient (2.1%; esophageal fistula). In multivariate analysis, neutrophil-to-lymphocyte ratio (NLR) > 3 (p = 0.026) was significantly associated with poor survival.

Conclusion: Definitive radiotherapy of 60Gy with VMAT is feasible and safe for patients with esophageal cancer. Pre-treatment NLR >3 was an independent prognostic factor for OS.