Pembrolizumab vs chemotherapy in elderly patients with NSCLC: A comparative analysis of survival and adverse effects.

Abstract

e20528 Background: Elderly patients with non-small cell lung cancer (NSCLC) require treatment strategies that balance efficacy and tolerability. Immunotherapy with pembrolizumab has emerged as a potential alternative to traditional platinum/taxane-based chemotherapy. This study compares mortality and adverse effects between these two regimens in patients aged 75 years and older. Methods: This retrospective analysis utilized the TriNetX database. Elderly patients with NSCLC were divided into two cohorts: the first cohort received pembrolizumab (1,556 patients), and the second received platinum/taxane-based chemotherapy (1,556 patients). Propensity score matching was used to balance baseline characteristics. Kaplan-Meier survival analysis was performed to assess mortality and adverse effects, with hazard ratios (HRs) calculated to evaluate relative risks. Results: Mortality was similar between the groups (HR: 1.069, 95% CI: 0.975–1.171, p=0.523). However, adverse effects were significantly higher in the chemotherapy group. Pembrolizumab reduced the risk of anemia (HR: 0.709, 95% CI: 0.636-0.790, p<0.001), neutropenia (HR: 0.357, 95% CI: 0.287–0.443, p<0.001), thrombocytopenia (HR: 0.698, 95% CI: 0.560–0.869, p=0.001), fever (HR: 0.774, 95% CI: 0.629–0.952, p=0.001), pneumonitis (HR: 0.470, 95% CI: 0.316–0.701, p=0.012), colitis (HR: 0.535, 95% CI: 0.391–0.732, p<0.001). Conversely, chemotherapy had a lower risk of chronic kidney disease (HR: 1.347, 95% CI: 1.162–1.561, p<0.001) and heart failure (HR: 1.328, 95% CI: 1.123–1.571, p=0.012). Myocarditis was rare, occurring only with pembrolizumab patients(0.6% vs. 0%, p=0.002). Conclusions: Pembrolizumab offers comparable survival to platinum/taxane-based chemotherapy while significantly reducing the risk of adverse effects such as neutropenia, thrombocytopenia pneumonitis, colitis, and anemia in elderly NSCLC patients. Although pembrolizumab is associated with a rare risk of myocarditis and higher chronic kidney disease incidence, its favorable safety profile makes it a preferred treatment option for this population. The large sample size strengthens the reliability of these findings for outcomes in elderly NSCLC patients. Outcome Hazard Ratio (95% CI) P-Value Favors Mortality 1.069 (0.975-1.171) 0.523 No significant difference Anemia 0.709 (0.636-0.790) <0.001 Pembrolizumab Neutropenia 0.357 (0.287-0.443) <0.001 Pembrolizumab Thrombocytopenia 0.698 (0.560-0.869) 0.001 Pembrolizumab Fever 0.774 (0.629-0.952) 0.001 Pembrolizumab Pneumonitis 0.470 (0.316-0.701) 0.012 Pembrolizumab Colitis 0.535 (0.391-0.732) <0.001 Pembrolizumab CKD 1.347 (1.162-1.561) <0.001 Chemotherapy Heart Failure 1.328 (1.123-1.571) 0.012 Chemotherapy