Concurrent Chemoradiotherapy Versus Radiation Monotherapy for Patients with Locally Advanced Esophageal Squamous Cell Carcinoma in the Era of Intensity Modulated Radiotherapy: A Propensity Score-matched Analysis

BACKGROUND To investigate the survival benefit of concurrent chemoradiotherapy (CCRT) for patients with locally advanced esophageal squamous cell carcinoma (ESCC) during the years of intensity-modulated radiotherapy (IMRT). METHODS Medical records of 1089 patients with ESCC who received IMRT from January 2005 to December 2017 were retrospectively reviewed. A total of 617 patients received CCRT, 472 patients received radiotherapy (RT) alone. Propensity score matching (PSM) method was used to eliminate baseline differences between the two groups. Survival and toxicity profile were evaluated afterward. RESULTS After a median follow-up time of 47.9 months (3.2-149.8 months), both overall survival (OS) and progression-free survival (PFS) of the CCRT group were better than those of the RT alone group, either before or after PSM. After PSM, the 1-, 3-, and 5-year OS of RT alone and CCRT groups were 59.0% versus 70.2%, 27.7% versus 40.5% and 20.3% versus 33.1%, respectively (p < 0.001). The 1-, 3-, and 5-year PFS were 39.4% versus 49.0%, 18.3% versus 30.4% and 10.5% versus 25.0%, respectively (p < 0.001). The rates of ≥ grade 3 leukopenia and radiation esophagitis in the CCRT group were higher than that of RT alone group (p < 0.05). There was no significant difference in the probability of radiation pneumonitis between the two groups (p = 0.167). Multivariate Cox analysis indicated that female, EQD2 ≥60 Gy and concurrent chemotherapy were favorable prognostic factors for both OS and PFS. CONCLUSIONS Concurrent chemotherapy can bring survival benefits to patients with locally advanced ESCC receiving IMRT. For patients who cannot tolerate concurrent chemotherapy, RT alone is an effective alternative with promising results.