Immune checkpoint inhibitors (ICIs) for second-line retreatment in esophageal cancer progressing after first-line immunotherapy: a single-center retrospective cohort study

Abstract

Background Controversy continues regarding whether immunosuppressive agents can be used across treatment lines after disease progression on first-line immunotherapy for advanced esophageal cancer. The aim of this study is to evaluate the efficacy and safety of immune checkpoint inhibitor (ICI) retreatment through real-world data. Methods The clinical data of patients with esophageal cancer treated at The First Affiliated Hospital of Henan University of Science and Technology were retrospectively collected. All patients received first-line combination therapy with programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1) inhibitors for more than 3 months, and following disease progression, received second-line therapy with PD-1/PD-L1 inhibitors for at least two cycles. Treatment efficacy and safety were evaluated. Results In the overall population, the median overall survival (mOS) was 10.0 months [95% confidence interval (CI): 9.5–10.5] and the median progression-free survival (mPFS) was 4.4 months (95% CI: 4.1–4.5). The objective response rate (ORR) was 33.2%, and the disease control rate (DCR) was 65.9%. The Cox regression model analysis identified first-line PFS >6 months as an independent prognostic factor for both second-line PFS and OS. Safety was manageable, and no treatment-related deaths occurred. Conclusions The results of this study suggest that ICI retreatment showed measurable activity in a selected real-world cohort and deserves further evaluation in comparative studies.