Impact of immunotherapy era on survival in stage IV non–small cell lung cancer.

8562 Background: The introduction of immunotherapy (IO) has transformed treatment paradigms in Stage IV non-small cell lung cancer (NSCLC). However, large-scale population-based evidence quantifying its impact on survival remains limited. We evaluated overall survival trends before and after the IO era using SEER data. Methods: We identified patients diagnosed with Stage IV NSCLC from 2006 to 2020 in the SEER 17 database. Patients were grouped by era: pre-IO (2006–2014) and post-IO (2015–2020). Demographics, histology, and socioeconomic variables were included. Overall survival (OS) was assessed using Kaplan-Meier analysis. Multivariable Cox proportional hazards models estimated hazard ratios (HRs) with 95% confidence intervals (CIs) adjusting for age, sex, race, and histology. Results: A total of 101,243 Stage IV NSCLC patients were included. The post-IO era was associated with a 19% reduction in mortality compared to the pre-IO era (HR 0.81; 95% CI 0.79–0.82; p<0.001). Older age (≥75 years) conferred increased mortality risk (HR 1.32; 95% CI 1.30–1.34; p<0.001), while younger patients (<65 years) had better outcomes (HR 0.91; 95% CI 0.89–0.93; p<0.001). Male sex (HR 1.16; 95% CI 1.14–1.17; p<0.001), non-adenocarcinoma histology (HR 1.30; 95% CI 1.28–1.32; p<0.001), and Black race (reference group) were independently associated with worse survival. White (HR 0.83; 95% CI 0.81–0.85; p<0.001) and Other races (HR 0.75; 95% CI 0.73–0.77; p<0.001) demonstrated survival advantages. Kaplan-Meier curves confirmed significantly improved OS in the post-IO era (median OS 8 vs 10 months, log-rank p<0.001). Conclusions: This large population-based study confirms a significant survival benefit in Stage IV NSCLC patients diagnosed in the immunotherapy era, alongside expected demographic and histologic disparities. These findings support the real-world impact of immunotherapy and underscore the need for continued efforts to address survival inequities.