Background: Lung cancer is a leading cause of cancer mortality in the United States, with Non-small cell lung cancer (NSCLC) being the most common subtype. Under the Affordable Care Act, 39 states adopted Medicaid Expansion (ME) in 2014, while 12 did not. ME improved insurance coverage and lung cancer screening rates. This study examined the association between ME and NSCLC stage at diagnosis and treatment rates. Methods: We performed a retrospective observational study using Surveillance, Epidemiology, and End Results (SEER) database including patients aged 55-64 diagnosed with NSCLC from 2007 to 2021. Multivariate logistic regression analysis was performed to compare the odds of Early NSCLC diagnosis (Stages 1 and 2) and odds of treatment for early NSCLC between ME states and non-ME states before and after 2014. Results: During the study period, 191,785 patients were diagnosed with NSCLC, of which 42,338 were early NSCLC. The odds of early NSCLC diagnosis and treatment in early NSCLC were similar in ME and non-ME states before 2014. After 2014, the odds of early NSCLC diagnosis were significantly higher in ME states [AOR-1.53 (1.45-1.63)] compared to non-ME states [AOR-1.34 (1.25-1.44)]. However, there was no significant difference in odds of treatment for early NSCLC in ME states [1.36 (1.01 -1.81) and non-ME states 1.25 (0.93-1.68) after 2014. Conclusions: We conclude that ME is associated with increased odds of early-stage diagnosis of NSCLC. However, the odds of receipt of treatment were not affected. These findings highlight the benefits of ME as an effective strategy to improve access to care, but also underscore that other barriers to receiving treatment exist despite early diagnosis. Further studies are warranted to identify the barriers and potential limitations of policy change to improve outcomes.

NSCLC- Non-Small Cell Lung Cancer, ME- Medicaid Expansion.