Clinical outcomes and toxicities of locally advanced esophageal squamous cell carcinoma patients treated with early thoracic radiation therapy after induction chemotherapy.

Objective: The purpose of this study was to compare the clinical outcomes and toxicities between induction chemotherapy (IC) + chemo-radiotherapy (CRT) and CRT alone in patients with locally advanced esophageal squamous cell carcinoma (ESCC), to explore the appropriate thoracic radiotherapy (TRT) timing after IC and to identify prognostic factors.
Methods: 450 ESCC patients were included from September 2011 to December 2020, 238 of whom received IC/CRT. Propensity score matching was performed to balance potential confounders between the two groups. Multivariate Cox regression analysis was used to identify the independent prognostic factors.
Results: Patients who received IC/CRT experienced improved overall survival (OS) (38.5 vs. 28.8 months) and progression-free survival (PFS) (41.0 vs. 22.0 months) before matching, with similar results after matching. In the IC/CRT group, early TRT had more favorable survival than late TRT both matching before and after. In subgroup analysis, early TRT combination concurrent chemotherapy had better OS and PFS than late TRT combination concurrent chemotherapy. In addition, early TRT had better survival benefits regardless of the N stage. Notably, the IC/CRT group and early TRT group had manageable toxicities reaction compared with CRT alone group and the late TRT group. The nomogram was developed to predict the OS and PFS based on multivariate analysis results. The C-index was 0.743 and 0.722, respectively.
Conclusion: IC/CRT and early TRT could yield satisfactory clinical outcomes and controllable toxicities in locally advanced ESCC. The IC plus early concurrent CRT might be a promising treatment strategy for improving further survival in ESCC.
(© 2023. The Author(s) under exclusive licence to Japan Society of Clinical Oncology.)