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Published on: May 20, 2016
Geographic Access to Low-Dose CT Lung Cancer Screening in Tennessee: Disparities by Socioeconomic Variables,
Sima Namin1, Martin Whiteside2, R Eric Heidel3
1College of Medicine-Knoxville, Office of Research Support, University of Tennessee Health Science Center, Knoxville, Tennessee, USA.
Introduction:
Lung cancer screening enables earlier detection and improved outcomes, yet geographic inequities persist in access to low-dose computed tomography (LDCT). We quantified tract-level access to LDCT screening in Tennessee and examined disparities by rurality and Appalachian status.
Methods:
We compiled an inventory of LDCT-capable sites and measured access using a 30-min enhanced two-step floating catchment area (E2SFCA) index with three banded decay weights. Access was compared across four strata (urban Appalachia, rural Appalachia, urban non-Appalachia, and rural non-Appalachia) using Kruskal-Wallis and pairwise Wilcoxon tests (Holm adjustment). Rank-based associations between E2SFCA and tract sociodemographics were evaluated using Spearman correlations.
Results:
We identified 198 LDCT sites in Tennessee. Urban residents account for 74.10% of those living within ≤20 min, whereas rural residents constitute the majority (63.50%) of the 30-45-min band. Access differed across strata (Kruskal-Wallis χ2 = 277.46, p < 2.2 × 10-16): Medians (per 1000) were highest in urban non-Appalachia (0.464) and urban Appalachia (0.430), and lower in rural Appalachia (0.210) and rural non-Appalachia (0.197); all urban-rural contrasts were significant. Regional patterns diverged: West Tennessee showed the largest coverage gap (13.9% zero-access tracts), East Tennessee had the lowest capacity among served tracts (median = 0.339; overall median = 0.293), and Middle Tennessee showed the strongest overall access (overall median = 0.380; 73/647 zero-access; 11.3%).
Conclusions:
Rural communities face longer travel times to access LDCT screening sites with more zero-access tracts than urban communities. Our findings support interventions such as adding service points in West Tennessee and expanding capacity in East Tennessee. Strengthening navigation and referral pathways for rural and Appalachian residents is also necessary.
