Molecular Testing Among Patients With Advanced Non–Small Cell Lung Cancer in the Rural US
Dena P. Rhinehart, Evelien van Gelderen, Josephine Feliciano, Craig Evan Pollack, Kristen A. Marrone, Amanda L. BlackfordImportance
Molecular evaluation is standard of care for patients with advanced non–small cell lung cancer (NSCLC) in the US. Patients in rural areas face disproportionate lung cancer mortality associated with reduced guideline-concordant evaluation and treatment receipt, but molecular testing patterns have not been described in this population.
Objective
To characterize molecular testing patterns in the rural US following initial testing implementation.
Design, Setting, and Participants
This cohort study used the Surveillance, Epidemiology, and End Results Program linked to Medicare claims data to identify individuals aged 66 years or older diagnosed with advanced NSCLC from January 2014 to December 2019. Data analysis was performed from December 2025 to August 2026.
Exposures
Sociodemographic variables, histology, and practitioner visits.
Main Outcomes and Measures
The primary outcome was receipt of molecular testing. The cumulative incidence of testing overall and by patient subgroups defined at baseline were calculated using the total person-time at risk (30 days before diagnosis to death or 6 months after diagnosis) using a competing-risks framework, with death as the competing event.
Results
Among a total of 8259 Medicare beneficiaries residing in rural areas who were diagnosed with advanced NSCLC included in the study (mean [SD] age, 76.1 [6.7] years; 4672 males [56.6%]), 1775 (21.5%) were eligible for Medicaid, 3754 (45.5%) had adenocarcinoma histology, 2044 (24.7%) had squamous histology, and 2461 (29.8%) had other or unspecified histology. In the cohort, 2963 (35.9%) received molecular testing. The cumulative incidence of testing by 180 days after diagnosis was 0.36 (95% CI, 0.35-0.37). Increasing age (hazard ratio [HR], 0.96 [95% CI, 0.93-0.99]), later diagnosis year (HR, 1.05 [95% CI, 1.02-1.07]), dual Medicaid coverage (HR, 0.71 [95% CI, 0.64-0.79]), Part D enrollment (HR, 1.13 [95% CI, 1.04-1.22]), and squamous histology (HR, 0.35 [95% CI, 0.32-0.39]) were independently associated with testing. A greater percentage of patients who received testing had visits with both a proceduralist or a surgeon and an oncologist compared with those without testing (1257 [77.7%] vs 867 [58.9%];
Conclusions and Relevance
In this cohort study of Medicare beneficiaries with advanced NSCLC residing in the rural US, initial receipt of molecular testing was low. Dual Medicaid coverage, Part D enrollment, and subspecialist visits were independently associated with test receipt, highlighting key areas for future study to promote equitable delivery of guideline-concordant lung cancer care.