Abstract A054: Disparities in the availability of neuro-oncology clinical providers and infrastructure in the United States
Authors: Kim Yeonju , Armstrong Terri S. , Gilbert Mark R. , Celiku Orieta 
Published: January 2023

Abstract
BACKGROUND: Barriers to clinical trial access have significant implications for patient care. Motivated by previous work which identified geographical and socioeconomic disparities in neuro-oncology trials’ accessibility in the United States (US), we assessed the role of these factors on the availability of neuro-oncology providers and member institutions of trial collaboratives and community outreach programs. METHODS: US Census data on population and geography and the Neighborhood Atlas’ Area Deprivation Index (ADI) were obtained. Data on UCNS-certified neuro-oncology subspecialists, NRG Oncology Main Member institutions, and NCI Community Oncology Research Program (NCORP) sites were obtained and mapped to 5-digit zip code tabulation areas (ZCTAs) using Google Geocode. Linear and logistic regression and spatial analyses were conducted in R using the spdep and spatialreg libraries, to assess the role of geography, disadvantage, and population on infrastructure accessibility. RESULTS: We identified 316 neuro-oncologists, 130 NRG institutions, and 963 NCORP sites, in 0.6%, 0.4%, and 2.2% of all ZCTAs in the US (N = 33120), respectively. Neuro-oncologists and NRG institutions were more likely to exist in more populated (OR=1.86, p&lt;0.001; OR=1.80, p&lt;0.001) and less-disadvantaged (OR=0.98, p&lt;0.001; OR=0.98, p&lt;0.001) regions, reflecting urban-rural and socioeconomic disparities. Moreover, neuro-oncologists were more likely to exist in geographically adjacent regions (OR=320.594, p&lt;0.001), while NRG institutions were geographically more broadly distributed (OR=1.49, p=0.859). Where existent, a greater number of neuro-oncologists served less-disadvantaged regions (β=-0.014, p=0.021), while the number of NRG institutions was more equitably distributed overall (Moran’s I data=0.002, p=0.394; Moran’s I residuals=0.002, p=0.489; population: β=0.004, p=0.778; ADI: β=-0.0001, p=0.919). On the other hand, NCORP sites were more likely to exist in areas of greater disadvantage (OR=1.01, p=0.001), reflecting the NCORP mission to reach more diverse communities. However, NCORP sites were more likely to exist and were more prevalent among more populated (OR=2.79, p&lt;0.001; β=0.076, p=0.007) and geographically adjacent regions (OR=8.23, p&lt;0.001; ρ=0.120, p&lt;0.001), reflecting urban-rural disparities. CONCLUSION: The identified disparities in availability of neuro-oncologists and institutions capable of hosting clinical trials may explain the previously reported disparities in trial sites. Disparities in neuro-oncologist availability suggest the need for neuro-oncology specific measures involving telehealth and local oncologists. The more equitable geographic and socioeconomic distribution of NRG institutions, and the more equitable socioeconomic distribution of NCORP sites reaffirm the importance of the mission and ability of such initiatives to bridge geographic and socioeconomic barriers. Finally, the existence of disparities across all infrastructure levels raises the concern that these disparities reflect broader disparities in access to neuro-oncology care.
Citation Format: Yeonju Kim, Terri S. Armstrong, Mark R. Gilbert, Orieta Celiku. Disparities in the availability of neuro-oncology clinical providers and infrastructure in the United States [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr A054.