Poverty, Travel Time Drive Disparities in Access to National Cancer Institute-Designated Centers

December 15, 2017

Patient access to NCI Cancer Centers is influenced by a complex mix of cancer center distribution and density, ethnicity, urbanicity, and travel time to care, according to a recently published statistical model.

Patient access to National Cancer Institute (NCI) Cancer Centers is influenced by a complex mix of cancer center distribution and density, ethnicity, urbanicity, and travel time to care, according to a statistical model published in the Journal of Medical Systems

Previous research has shown that longer travel time to cancer care services increases the risks of diagnosis with cancer at advanced stages, treatment noncompliance, and nonparticipation in clinical trials, the authors noted.

Racial and income-associated disparities in access to cancer care have been better studied than geographic barriers to care. Ethnic and racial minorities, individuals with low socioeconomic status, and residents in certain geographic areas have all been found to suffer from intersecting barriers to care, the authors noted. The uneven geographic distributions and densities of major cancer centers across the United States contributes to disparities in access. For rural residents, season, low income level, and distance from treatment centers can conspire to impede timely access to care. Rural residents also tend to have poorer access to preventive or screening services, diagnostic services, and cancer survivorship care. A trend in recent years toward more rural hospital closures is exacerbating these issues for many Americans.

NCI-designated Cancer Centers must meet rigorous criteria and demonstrate “scientific excellence” and the capability for multidisciplinary care and research. Nationwide, there are 69 NCI Cancer Centers in 35 states and Washington, D.C.

The authors sought to use advanced multivariate geographic analysis tools to assess both geographic and racial associations in geographic disparities in cancer care, in order to inform considerations of how to best mitigate those disparities. They used a Geographic Information System–based generalized two-step floating catchment area (G2SFCA) analytical model to assess the degree of geographic access to NCI Cancer Centers. The model accounts for competition intensity for services at different centers, as well as travel time.

Accessibility declined with travel time but that association was influenced by a “complex interaction” between the centers and catchment populations, “both of which are distributed far from uniformly,” the authors noted.

The proportion of populations under the poverty line were “disproportionately concentrated” in low-accessibility areas.

“Urban advantage is pronounced at the county level as the average accessibility is highest in large central metro areas,” followed by medium metro areas, small cities, and rural areas, they reported. Accessibility in urban clusters was, however, “slightly lower” than in rural areas, possibly because of more competition intensity for services.

Perhaps surprisingly, overall, whites had the lowest geographic accessibility levels to NCI Cancer Centers, followed by Hispanic, African-American, and Asian populations (Ps < .001)-a “reversed racial disadvantage”, which was a somewhat counterintuitive finding consistent with at least one prior study, the authors reported. One factor possibly accounting for the finding is the ready availability of public transportation to low-income people in urban areas.

The reversed racial disadvantage findings were based on ecological or geographic population data and not actual utilization of services at each facility for different ethnic populations, and future research should focus on center visit demographics, the authors cautioned. They did not study the effect of community oncology centers.