Impact of Radiation Dose on Survival for Esophageal Squamous Cell Carcinoma Treated With Neoadjuvant Chemoradiotherapy.

ABSTRACT

Purpose: Radiation dose used in the neoadjuvant chemoradiotherapy (NCRT) for patients with locally advanced esophageal squamous cell carcinoma (ESCC) varies in different trials and clinical practice. Methods and Materials Data from patients diagnosed with ESCC receiving NCRT followed by esophagectomy were retrospectively collected from February 2013 to December 2017. Lower dose (LD) radiotherapy was defined as ≤45 Gy, and >45 Gy was considered as higher dose (HD). Survival rates were calculated by the Kaplan-Meier method and compared with long-rank test. Multivariate Cox regression analyses were performed to identify variables associated with survival. Results: A total of 118 patients treated with NCRT were included in our analysis: 62 patients received LD radiotherapy, and 56 patients received HD radiotherapy. The median follow-up time was 24.3 months (0.67-65.3 m). Two-years overall survival (OS) rates were 75.0 and 79.0% in HD and LD group, respectively (P = 0.360), and complete pathological remission (pCR) rates in two groups were 42.9 and 30.6%, respectively (P = 0.17). The incidences of toxic effects including post-operative complications were not significantly different between two groups. Multivariate analysis showed that tumor T stage, M1a disease, smoking history, and pCR rate were significantly associated with OS. Conclusions: In ESCC patients treated with NCRT followed by surgery, higher radiation dose was not significantly associated with a higher pCR rate and longer survival. Lower radiation dose might be a preferable time-dose fraction scheme. Our finding needs to be further validated by randomized trials.