Influence of radiotherapy interruption on esophageal cancer with intensity-modulated radiotherapy: a retrospective study

Abstract Background Radiotherapy interruption (RTI) prolongs the overall total treatment time and leads to local control loss in many cancers, but it is unclear in esophageal cancer. We aimed to evaluate the influence of RTI on the overall survival (OS), progression-free survival (PFS), and local-regional recurrence-free survival (LRFS) of patients with esophageal cancer undergoing chemoradiotherapy. Methods A total of 299 patients with esophageal squamous cell carcinoma from 2017 to 2019 were retrospectively analyzed to investigate the effect of RTI on OS, PFS, and LRFS. The delayed time of radiotherapy interruption was calculated as the actual radiation treatment time minus the scheduled time. The univariate and multivariate analyses were performed by the COX proportional hazards regression models, and the survival analysis was performed through the Kaplan‒Meier method, and compared with the log-rank test. Results The 3-year OS, PFS, and LRFS rates were 53.0%, 42.0%, and 48.0%, respectively. The univariate and multivariate analyses showed that the delayed time > 3 days was an independent adverse prognostic factor for OS (HR = 1.68, 95% CI 1.10–2.55, p = 0.016), and LRFS (HR = 1.74, 95% CI 1.18–2.57, p = 0.006). The patient with a delayed time of > 3 days had poorer survival rates of OS, and LRFS than patients with a delayed time of ≤ 3 days (OS, p = 0.047; LRFS, p = 0.013), and the survival outcomes of patients with shorter delayed time (1–3 days) were slightly different from the patients without interruptions. The impact of delay time on PFS is not statistically significant, but the survival outcomes of the two groups were slightly different. Conclusion There was a significant correlation between delayed time and local control of esophageal cancer. The delayed time for more than 3 days might decrease the survival outcome, and increase the local recurrence risk.