Radiotherapy Deserts: The Impact of Race, Poverty, and the Rural-Urban Continuum on Density of Providers and the Use of Radiation Therapy in the US

• Published in: International journal of radiation oncology, biology, physics Vol. 116; no. 1; pp. 17 - 27
• Main Authors: LaVigne, Anna W., DeWeese, Theodore L., Wright, Jean L., Deville, Curtiland, Yegnasubramanian, Srinivasan, Alcorn, Sara R.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2023
• Subjects: Aged; Breast Neoplasms - economics; Breast Neoplasms - epidemiology; Breast Neoplasms - ethnology; Breast Neoplasms - radiotherapy; Databases, Factual - statistics & numerical data; Female; Health Personnel - statistics & numerical data; Health Services Accessibility - statistics & numerical data; Health Services Needs and Demand - statistics & numerical data; Healthcare Disparities - economics; Healthcare Disparities - ethnology; Healthcare Disparities - statistics & numerical data; Humans; Male; Medicare - statistics & numerical data; Neoplasms - economics; Neoplasms - epidemiology; Neoplasms - ethnology; Neoplasms - radiotherapy; Patient-Centered Care - statistics & numerical data; Poverty - statistics & numerical data; Prostatic Neoplasms - economics; Prostatic Neoplasms - epidemiology; Prostatic Neoplasms - ethnology; Prostatic Neoplasms - radiotherapy; Race Factors - statistics & numerical data; Radiotherapy - economics; Radiotherapy - standards; Radiotherapy - statistics & numerical data; Resource-Limited Settings - statistics & numerical data; Rural Population - statistics & numerical data; Social Class; United States - epidemiology; Urban Population - statistics & numerical data; United States
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2023.01.046

Prior efforts to characterize disparities in radiation therapy access and receipt have not comprehensively investigated interplay between race, socioeconomic status, and geography relative to oncologic outcomes. This study sought to define these complex relationships at the US county level for prostate cancer (PC) and invasive breast (BC) cancer to build a tool that facilitates identification of “radiotherapy deserts”—regions with mismatch between radiation therapy resources and oncologic need. An ecologic study model was constructed using national databases to evaluate 3,141 US counties. Radiation therapy resources and use densities were operationalized as physicians to persons at risk (PPR) and use to persons at risk (UPR): the number of attending radiation oncologists and Medicare beneficiaries per 100,000 persons at risk, respectively. Oncologic need was defined by “hot zone” counties with ≥2 standard deviations (SDs) above mean incidence and death rates. Univariable and multivariable logistic regressions examined links between PPR and UPR densities, epidemiologic variables, and hot zones for oncologic outcomes. Statistics are reported at a significance level of P < .05. The mean (SD) PPR and UPR densities were 2.1 (5.9) and 192.6 (557.6) for PC and 1.9 (5.3) and 174.4 (501.0) for BC, respectively. Counties with high PPR and UPR densities were predominately metropolitan (odds ratio [OR], 2.9-4.4), generally with a higher percentage of Black non-Hispanic constituents (OR, 1.5-2.3). Incidence and death rate hot zones were largely nonmetropolitan (OR, 0.3-0.6), generally with a higher percentage of Black non-Hispanic constituents (OR, 3.2-6.3). Lower PPR density was associated with death rate hot zones for both types of cancer (OR, 0.8-0.9); UPR density was generally not linked to oncologic outcomes on multivariable analysis. The study found that mismatch between oncologic need with PPR and UPR disproportionately affects nonmetropolitan communities with a higher percentage of Black non-Hispanic constituents. An interactive web platform (bit.ly/densitymaps) was developed to visualize “radiotherapy deserts” and drive targeted investigation of underlying barriers to care in areas of highest need, with the goal of reducing health inequities in this context.