County-level rural-urban variation in NSCLC treatment and survival among Medicare beneficiaries.

Abstract

209 Background: Patients with non-small cell lung cancer (NSCLC) living in rural areas face numerous barriers to care. Although rural-urban disparities in lung cancer care are well documented, less is known about variation in treatment and survival across rural and urban counties or how these patterns have changed over time. Methods: We conducted a retrospective study of Medicare beneficiaries aged ≥67 years diagnosed with NSCLC from 2013-2021 using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. We estimated county-level risk-standardized rates of appropriate treatment, based on NCCN guidelines, and 1-year survival using mixed-effects models adjusted for demographic and clinical characteristics. Counties with < 20 patients were excluded to ensure stable rate estimates. Counties were classified as rural or urban using the Rural-Urban Continuum classification and grouped into deciles for each outcome. Temporal changes in outcomes were evaluated by comparing risk-standardized treatment rates between 2013-2016 and 2017-2021 using the Wilcoxon rank-sum test. Results: The analysis included 82,692 patients in 489 counties (50.7% rural). The median treatment rates for rural counties were 57.6% (IQR 55.4-59.6%) and 59.6% (IQR 57.4-62%) for urban counties, and the median 1-year survival rates were 47.9% (IQR 46.3-49.4%) and 48.9% (IQR 47.4-50.9%), respectively. Rural counties were disproportionately represented among lower-performing counties for both treatment and survival outcomes. For example, 14.9% of rural counties were in the lowest decile of treatment performance, compared to 5.0% of urban counties (p<0.001). Similarly, 15.3% of rural counties were in the lowest decile for one-year survival, compared to 4.6% of urban counties (p<0.001). Despite these differences, substantial heterogeneity was observed within both rural and urban counties, with 8.5% of rural counties performing above the 75th percentile of urban counties and 10.4% of urban counties performing below the 25th percentile of rural counties for treatment outcomes. Rates of appropriate treatment worsened in rural counties, with median adjusted rates declining from 57.7% in 2013–2016 to 57.2% in 2017–2021, with increasing rates in urban counties, where adjusted treatment rates increased from 58.2% to 59.9% (P-value for difference in deltas < 0.001). Rates of 1-year survival improved slightly in rural counties, with median adjusted rates increasing from 44.7% to 46.9%, while 1-year survival rates in urban counties increased significantly more, from 44.1% to 49.1% (P-value for difference in deltas < 0.001). Conclusions: Rural counties experienced worse NSCLC treatment and survival outcomes, with disparities widening over time. However, substantial variation within rural regions suggest high-performing counties may provide important lessons for improving cancer care in underserved communities.