Once unthinkable: Population-level changes in five-year survival for metastatic non–small cell lung cancer in the immunotherapy era.

e20696 Background: Five-year survival in metastatic non–small cell lung cancer (NSCLC) was historically rare. The introduction of immune checkpoint inhibitors has altered treatment paradigms, yet population-level evidence of long-term survival gains—and whether these gains extend across racial groups—remains limited. Methods: We performed a retrospective population-based cohort study using Surveillance, Epidemiology, and End Results (SEER) data to identify patients with de novo stage IV NSCLC diagnosed between 2010 and 2017. Five-year lung cancer–specific survival was estimated for non-Hispanic White (NHW) and non-Hispanic Black (NHB) patients using SEER*Stat. Temporal trends were analyzed using Joinpoint regression to assess changes over time. Results: Five-year survival for metastatic NSCLC nearly doubled during the study period, rising from approximately 6% in 2010 to 11–12% by 2017. Statistically significant annual improvements were observed in both non-Hispanic White (NHW) and non-Hispanic Black (NHB) populations. Survival trends remained parallel over time, with no statistically significant interaction between race and year of diagnosis (interaction p > 0.05). Conclusions: Population-level five-year survival for metastatic NSCLC has improved substantially in the immunotherapy era. Parallel survival gains among NHW and NHB patients suggest that advances in systemic therapy have translated into broadly shared long-term benefits. These findings support population health and policy efforts focused on equitable access to immunotherapy to sustain and extend survival gains nationwide.