The impact of county-level radiation oncologist density on prostate cancer mortality in the United States.

BACKGROUND: The distribution of radiation oncologists across the United States varies significantly among geographic regions. Accompanying these variations exist geographic variations in prostate cancer mortality. Prostate cancer outcomes have been linked to variations in urologist density, however, the impact of geographic variation in the radiation oncologist workforce and prostate cancer mortality has yet to be investigated. The goal of this study was to determine the effect of increasing radiation oncologist density on regional prostate cancer mortality.
METHODS: Using county-level prostate cancer mortality data from the National Cancer Institute and Centers for Disease Control as well as physician workforce and health system data from the Area Resource File a regression model was built for prostate cancer mortality controlling for categorized radiation oncologist density, urologist density, county socioeconomic factors and pre-existing health system infrastructure.
RESULTS: There was statistically significant reduction in prostate cancer mortality (3.91-5.45% reduction in mortality) in counties with at least 1 radiation oncologist compared with counties lacking radiation oncologists. However, increasing the density of radiation oncologists beyond 1 per 100 000 residents did not yield statistically significant incremental reductions in prostate cancer mortality.
CONCLUSION: The presence of at least one radiation oncologist is associated with significant reductions in prostate cancer mortality within that county. However, the incremental benefit of increasing radiation oncologist density exhibits a plateau effect providing marginal benefit. In order to optimize outcomes a geographically aware policy, which addresses the size and distribution of the workforce, must be in place in order prevent geographic disparities in prostate cancer mortality.