Adding nivolumab to definitive chemoradiotherapy in patients with esophageal squamous cell carcinoma: a propensity score matching study

There were no clear evidence regarding the role of immune checkpoint inhibitors during concurrent chemoradiotherapy (CCRT) in patients with esophageal squamous cell carcinoma (ESCC). Herein, we conducted a retrospective study to analyze the benefits of nivolumab in combination with definitive CCRT for locally advanced ESCC patients. Patients with ESCC who underwent definitive CCRT between January 2020 and December 2025 were included in our study. Patients were categorized into two groups according to whether nivolumab was administered during definitive CCRT or not. Survival outcomes were estimated using the Kaplan–Meier method. Cox proportional hazards regression analysis was also performed to adjust for potential confounding factors. After propensity score matching, 69 matched pairs were included in the analysis. Median progression-free survival was 30.1 months in the Nivo-CCRT group versus 11.9 months in the CCRT group ( p < 0.001) and median overall survival was substantially longer in the Nivo-CCRT group than in the CCRT group (45.0 vs. 15.1 months, p < 0.001). Overall response rates were also significantly higher in the Nivo-CCRT group than in the CCRT group, accounting for 95% vs. 54%, respectively. Subgroup analysis found the efficacy was consistently toward Nivo-CCRT across all PD-L1 subgroups, although statistical evidence for interaction was not demonstrated. Grade 3–4 treatment-related adverse events were generally comparable between the two groups. Multivariate Cox regression analysis showed nivolumab with definitive CCRT was strongly correlated with survival. Adding nivolumab to definitive CCRT improved survival in patients with ESCC. Further prospective studies are warranted to confirm our conclusion.