ABSTRACT: The present study evaluated the impact of prior radiotherapy (RT) on patients with advanced non-small cell lung cancer (NSCLC) receiving therapy with immune checkpoint inhibitors (ICIs) and further assessed the prognostic factors in patients receiving both RT and ICI. Patients diagnosed with NSCLC at the Catholic Medical Center and Asan Medical Center between January 2016 and October 2020 and who received immunotherapy were retrospectively reviewed. Among 240 patients, poor Eastern Cooperative Oncology Group (ECOG) score, high PD-L1 expression, and ICI-related adverse events (AE) were significantly associated with progression-free survival (PFS) (HR, 2.654; 95% CI, 1.484-4.749; p = 0.001; HR, 0.645; 95% CI, 0.449-0.926, p = 0.017; HR, 0.430; 95% CI, 0.229-0.808; p = 0.009, respectively). Among patients who received both RT and immunotherapy, poor ECOG status, squamous cell carcinoma, and ICI-related AE were significant factors associated with poor PFS (HR, 2.430; 95% CI, 1.464-4.034; p = 0.001; HR, 0.667; 95% CI, 0.455-0.978, p = 0.038; HR, 0.520; 95% CI, 0.284-0.953, p = 0.034, respectively). The present study showed that prior RT showed no significant independent association with primary outcomes in patients with advanced NSCLC receiving immunotherapy. In patients who received both RT and immunotherapy, clinical parameters, including ICI-related AEs, were independently predictive of PFS.
