Effects of Radiotherapy on Survival of Esophageal Cancer Patients Receiving Immunotherapy: Propensity Score Analysis and Nomogram Construction

Abstract

Purpose: The present study assessed the effects of radiotherapy on overall survival (OS) and progression-free survival time (PFS) in patients with stage II or higher esophageal cancer receiving immunotherapy; evaluated factors independently prognostic of OS and PFS in these patients; and utilized these factors to establish a prognostic nomogram. Patients and Methods: This study enrolled 134 patients with stage II or higher esophageal cancer treated with chemotherapy (platinum-based agents plus paclitaxel or fluorouracil) and immunotherapy. These patients were divided into two groups, a radiotherapy (RT) group (n = 55) and a non-radiotherapy (non-RT) group (n = 79). Following 1:1 propensity score matching, OS and PFS were compared by the Kaplan–Meier method, and factors associated with survival were determined by univariate and multifactorial Cox regression analyses. These factors were used to construct a prognostic nomogram. Results: After propensity matching, all covariates were well balanced in the two groups (all P > 0.05). After matching, both median PFS (15.70 months [95% confidence interval (CI) 8.68–22.72 months] vs 5.70 months [95% CI 3.38–8.02 months], P = 0.002) and median OS (15.72 months [95% CI 12.94–18.46 months] vs 12.06 months [95% CI 9.91–14.20 months], P = 0.036) were significantly longer in the RT than in the non-RT group. Univariate and multifactorial analyses showed that RT, neutrophil-lymphocyte ratios, and tumor differentiation were independently prognostic of OS, with all hazard ratios (HRs) <1 and all P-values <0.05. A nomogram based on these factors was constructed, and its accuracy was verified. Conclusion: Immunotherapy plus RT resulted in better survival outcomes than immunotherapy alone. A nomogram based on prognostic factors can guide personalized treatment and monitor prognosis.