The association between breast cancer capacity and resources with incidence and mortality in Arizona's low populous counties

Introduction: While cancer deaths have decreased nationally, declines have been much slower in rural areas than in urban areas. Previous studies on rural cancer service capacity are limited to specific points along the cancer care continuum (eg screening, diagnosis or treatment) and require updating to capture the current rural health landscape since implementation of the 2010 Affordable Care Act in the USA. The association between current rural cancer service capacity across the cancer care continuum and cancer incidence and death is unclear. This cross-sectional study explored the association between breast cancer service capacity and incidence and mortality in Arizona's low populous counties.

Methods: To measure county-level cancer capacity, clinical organizations operating within low populous areas of Arizona were surveyed to assess on-site breast cancer services provided (screening, diagnosis and treatment) and number of healthcare providers were pulled from Centers for Medicare and Medicaid Services National Provider Identifier database. The number of clinical sites and healthcare providers were converted to county-level per capita rates. Rural-Urban Continuum codes were used to designate rural or urban county status. Age-adjusted county-level breast cancer incidence and death rates from 2010 to 2016 were obtained from the Arizona Department of Health Services, Arizona Cancer Registry. Descriptive statistics were used to summarize the results. Multivariate regression was used to evaluate the association between cancer service capacity and incidence and mortality in 13 out of Arizona's 15 counties.

Results: Rural counties had more per capita clinical sites (20.4) than urban counties (8.9) (p=0.02). Urban counties had more per capita pathologists (1.0) than rural counties (0) (p≤0.01). In addition to zero pathologists, rural counties had zero medical oncologists. Rural county status was associated with a decrease in breast cancer incidence (β=-20.1, 95% confidence interval: -37.2-3.1).

Conclusion: While Arizona's sparsely populated rural counties may have more physical infrastructure per capita, these services are dispersed over vast geographic areas. They lack specialists providing cancer services. Non-physician clinical providers may be more prevalent in rural areas and represent opportunities for improving access to cancer preventive services and care. Compared to urban counties, rural county status was associated with lower detected breast cancer incidence rates although there were no statistically significant differences in breast cancer mortality. Other factors may contribute to rural-urban differences in breast cancer incidence. Future research should explore these factors and the association between cancer capacity and local resources because the use of county-level data represents a challenge in Arizona, where counties average over 19 425 km2 (7500 square miles).