Abstract Background: Targeted therapies for non-small cell lung cancer (NSCLC) have led to population level improvements in mortality and can double overall survival for some patients with sensitizing mutations. Up to 60% of patients with advanced NSCLC may be eligible for these treatments, and US national oncology guidelines recommend molecular testing for patients with advanced disease. However, patients in the rural US are less likely than urban counterparts to receive molecular testing to determine eligibility for targeted therapies. The most rural populations also face twice the NSCLC mortality rate than the most urban populations, in part due to reduced access to guideline concordant care. Understanding the determinants of and processes involved in testing in the rural US is critical to develop strategies to deliver this care to this population with disproportionately high NSCLC mortality rates. In this study, we are examining patient level and systems level determinants of molecular testing in the rural US. Methods: Utilizing the SEER-Medicare database linked to federal housing assistance, we have identified a cohort of patients diagnosed with advanced NSCLC between 2014-2019 using the Surveillance, Epidemiology, and End Results (SEER) cancer registry program and Medicare database linked with data from the US Department of Housing and Urban Development. Individuals were 66 to 95 years old at diagnosis and continuously enrolled in fee-for-service Medicare for at least 12 months before diagnosis and either to death or six months after diagnosis. Molecular testing, as evidenced by epidermal growth factor receptor (EGFR) testing was identified via claims using HCPCS codes 81235, 81275, 81276, 81400-8, 81415, 81455, 81504, and 81540. We are also surveying multidisciplinary providers (pathologists, proceduralists, oncologists, nursing) to identify health system barriers and facilitators to molecular testing in the rural Mid-Atlantic. The survey questions were developed using the Consolidated Framework for Implementation Sciences (CFIR) 14-question survey as a guide. Results: We identified 8713 individuals with advanced NSCLC residing in a rural area at the time of diagnosis in the SEER-Medicare database. The overall rate of EGFR testing was 21.1%. Individuals tested were younger (75.1 v 76.3 years), more likely to be married (36.6% v 32.8%), did not originally qualify for Medicare due to disability (12.1% v 18.6%), did not have concurrent Medicaid coverage (13.9% v 23.3%) and had fewer comorbidities (Charlson score of 0, 46.2% v 40.6%), compared to those who did not have EGFR testing (p 0.001 for all). Provider survey responses are ongoing. Conclusions: This ongoing study is identifying specific rural US populations in greatest need of efforts to expand molecular testing for NSCLC as well as implementation barriers and facilitators to testing from a multidisciplinary perspective. Citation Format: Dena Rhinehart, Amanda L. Blackford, Kristen Marrone, Craig Pollack, Josephine Feliciano. Identifying determinants of molecular testing for advanced non-small cell lung cancer in the rural United States abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3675.
Rhinehart et al. (Fri,) studied this question.
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