Does greater oncologist density reduce estimates of Black-White disparities in cancer mortality

Background: Black-White racial disparities in cancer mortality in the US are well-documented. Oncologist density, as a measure of oncology care access, has the potential to improve cancer outcomes. Given the estimated shortage of oncologists over the next decade, understanding how oncologist density might influence cancer disparities is of considerable importance. We hypothesized that greater oncologist density was associated with smaller racial disparities in cancer mortality. Methods: An ecological study of 1,048 US counties was performed. Oncologist density (per 100,000 population) was calculated where oncologists were identified from the 2013 National Plan and Provider Enumeration System. Using the age-standardized cancer mortality rate between 2014-2018 from State Cancer Profiles, the Black:White cancer mortality rate ratio was calculated for each county. Linear regression was constructed to assess the association of oncologist density with (1) Black-White cancer mortality rate ratio, and (2) cancer mortality rates overall, and separately among Black and White people. Results: The mean Black:White cancer mortality rate ratio across US counties was 1.13. Every five additional oncologists per 100,000 population was associated with 0.02 increase in the Black:White cancer mortality rate ratio (95% confidence interval [CI]: 0.007 to 0.03) in the multivariable model. The role of oncologist density on cancer mortality was different between Black and White people. Every five additional oncologists per 100,000 population was associated with a 1.59 decrease per 100,000 population in cancer mortality rates among White people (95% CI: -2.96 to -0.23), whereas oncologist density was not associated with cancer mortality rates among Black people. Conclusions: Greater oncologist density was associated with larger Black-White racial disparities in cancer mortality. Greater oncologist density was associated with significantly lower cancer mortality among White patients, but not among Black patients. Increasing oncologist density alone could exacerbate mortality disparities, thus attention to ensuring equitable care is critical. Citation Format: Yuehan Zhang, Kathryn M. Leifheit, Otis W. Brawley, Roland Thorpe, Darrell Gaskin, Lorraine Dean. Does greater oncologist density reduce estimates of Black-White disparities in cancer mortality [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-177.