The clinical outcomes and tolerability of adding radiotherapy to first-line chemoimmunotherapy for treating patients with metastatic or relapsed esophageal squamous cell carcinoma: A retrospective cohort study.

Objective: This investigation sought to assess the clinical outcomes and safety of adding radiotherapy (RT) to first-line chemoimmunotherapy (CIT) for advanced esophageal squamous cell carcinoma (ESCC). Methodology: In this retrospective cohort study, patients with advanced ESCC (including metastatic or relapsed disease) who received first-line CIT at the Affiliated Hospital of Xuzhou Medical University between 2020 and 2023 were enrolled. Patients were categorized into the CIT alone and CIT plus RT (CI-RT) cohorts. Clinical outcomes and adverse events (AEs) were compared between the two cohorts. Results: This study enrolled 141 patients (CI-RT, n = 75; CIT, n = 66). The median follow-up duration was 31.7 months (95% confidence interval (CI): 24.5-38.9). The CI-RT cohort had significantly longer median PFS (16.2 vs. 9.3 months, hazard ratio (HR) = 0.652, P = 0.022) and median OS (25.2 vs. 14.6 months, HR = 0.591, P = 0.012) than did the CIT cohort. Multivariate analysis identified CI-RT as an independent predictor of both PFS (HR = 0.61, 95% CI: 0.42-0.89) and OS (HR = 0.57, 95% CI: 0.38-0.88). The incidence of grade ≥3 AEs did not significantly differ between the two cohorts (P = 0.810). Patients in the CI-RT cohort were associated with a higher incidence of esophagitis than were patients in the CIT cohort (16.0% vs. 1.5%, P = 0.003). One patient in the CIT cohort died from treatment-related pneumonitis. Conclusions: When first-line CIT is used for patients with advanced ESCC, the addition of RT can improve patient prognosis while maintaining favorable safety profiles.