Access to Lung Cancer Screening Services: Preliminary Analysis of Geographic Service Distribution Using the ACR Lung Cancer Screening Registry

Purpose: Lung cancer has the highest mortality rate among all types of cancer in the United States. The National Lung Screening Trial demonstrated that low-dose CT for lung cancer screening decreases both lung cancer-related mortality and all-cause mortality. Currently, the only CMS-approved lung cancer screening registry is the Lung Cancer Screening Registry (LCSR) administered by the ACR. The aims of this study were to assess access to lung cancer screening services as estimated by the number and distribution of screening facilities participating in the LCSR, by state, and to evaluate state-level covariates that correlate with access.

Methods: The ACR LCSR list of participating lung cancer screening facilities was used as a proxy for the availability of lung cancer screening facilities in each state. Additionally, we normalized the number of facilities by state by the number of screening-eligible individuals using Behavioral Risk Factor Surveillance System data. State-level demographics were obtained from the 2015 Behavioral Risk Factor Surveillance System: poverty level, insured population, unemployed, black, and Latino. State-specific lung cancer incidence and death rates, number of active physicians per 100,000, and Medicare expenditure per capita were obtained. Linear regression models were performed to examine the influence of these state-level covariates on state-level screening facility number. QGIS, an open-source geographic information system, was used to map the distribution of lung cancer screening facilities and to estimate the nearest neighbor index, a measure of facility clustering within each state.

Results: As of November 18, 2016, 2,423 facilities participated in the LCSR. When adjusted by the rate of screening-eligible individuals per 100,000, the median population-normalized facility number was 15.7 (interquartile range, 10.7-19.3). There was a positive independent effect (coefficient = 12.87; 95% confidence interval, 10.93-14.8) between state-level number of screening facilities and rate of screening-eligible individuals per 100,000. There were no significant correlations between number of facilities and lung cancer outcomes, state demographic characteristics, or physician supply and Medicare expenditure. In most states, facilities are clustered rather than dispersed, with a median nearest neighbor index of 0.65 (interquartile range, 0.51-0.81).

Conclusions: Facility number correlated with the rate of screening-eligible individuals per 100,000, a measure of the at-risk population. Alignment of screening facility number and distribution with other clinically relevant epidemiologic factors remains a public health opportunity.