Risk factors of esophageal fistula induced by re-radiotherapy for recurrent esophageal cancer with local primary site

Purpose The purpose of the present study was to investigate risk factors for esophageal fistula (EF) in patients with recurrent esophageal cancer receiving re-radiotherapy with or without chemotherapy. Methods We reviewed retrospectively the clinical characters and dosimetric parameters of 96 patients with recurrent esophageal cancer treated with re-radiotherapy in Cancer Hospital Affiliated to Shandong First Medical University between August 2014 and January 2021.Univariate and multivariate logistic regression analyses were provided to determine the risk factors of EF induced by re-radiotherapy. Results The median time interval between two radiotherapy was 23.35 months (range, 4.30 to 238.10 months). EF occurred in 19 patients (19.79%). In univariate analysis, age, T stage, the biologically equivalent dose in the re-radiotherapy, total biologically equivalent dose, hyperfractionated radiotherapy, ulcerative esophageal cancer, the length of tumor and the maximum thickness of tumor had a correlation with the prevalence of EF. In addition, age (HR = 0.170, 95%CI 0.030–0.951, p = 0.044), T stage (HR = 8.369, 95%CI 1.729–40.522, p = 0.008), ulcerative esophageal cancer (HR = 5.810, 95%CI 1.316–25.650, p = 0.020) and the maximum thickness of tumor (HR = 1.314, 95%CI 1.098–1.572, p = 0.003) were risk factors of EF in multivariate logistic regression analysis. Conclusions The incidence of EF was significantly increased in patients with recurrent esophageal cancer who underwent re-radiotherapy. This study revealed that age, T stage, ulcerative esophageal cancer and the maximum thickness of the tumor were risk factors associated with EF. In clinical work, patients with risk factors for EF ought to be highly concerned and individualized treatment plans should be taken to reduce the occurrence of EF.