Abstract
BACKGROUND: This study aimed to investigate the long-term clinical outcomes and toxicities of induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CCRT) vs. CCRT alone in patients with non-operable esophageal squamous cell carcinoma (ESCC). PATIENTS AND METHODS: Between 2008 and 2022, 271 ESCC patients who received definitive CCRT based on intensity modulated radiation therapy (IMRT)/volumetric modulated arc therapy (VMAT) were enrolled. Through a propensity score-matched (PSM) method, 71 patients receiving IC and CCRT were matched 1:1 to patients who received CCRT alone. The Kaplan-Meier method and Cox proportional hazards model were applied to analyze survival and prognosis. RESULTS: The IC + CCRT group had no improvement in 5-year overall survival (OS) rate, recurrence-free survival (RFS) rate, and distant metastasis-free survival (DMFS) rate (all p > 0.05) compared with the CCRT group. The 5-year OS rate (65.6% vs. 17.6% vs. 29.3%, p < 0.001), RFS rate (65.6% vs. 17.6% vs. 26.9%, p < 0.001), and DMFS rate (62.5% vs. 10.3% vs. 27.2%, p < 0.001) of the IC good responders were significantly higher than that of the IC poor responders and CCRT group. Multivariate analysis revealed that total radiotherapy time (≥ 49 days) and stage III/IV were independent predictive factors of OS, RFS, and DMFS. No significant differences were observed in the rates of grade 3-4 toxicities between both groups. CONCLUSIONS: Our results showed the addition of IC to CCRT was not superior to CCRT in unselected ESCC patients, while IC responders could benefit from this regime without an increase in toxicities.