Assessing populations with access to National Cancer Institute-funded sites using local distance-based service areas.

Introduction: Travel distance is a key barrier for patients to participate in clinical trials or receive cancer care. The National Cancer Institute (NCI) is a major funder of cancer research infrastructure through grant programs like the NCI Cancer Center (NCICC) and NCI Community Oncology Research Program (NCORP); however, the majority of US sites that care for people with cancer do not directly receive this funding. Methods: Through geospatial analysis we examined patient distance to NCI-funded sites and evaluated demographic subgroups to identify potential disparities in access to research opportunities. We assessed whether new NCI support to previously unfunded sites could address identified barriers in access. Results: NCI-funded sites tend to be in urban centers and are less accessible to low-income or rural patients. Nearly 17% of the US population over 35 years old would have to drive over 100 miles to obtain care at an NCI-funded site; only 1.6% would be beyond that distance when non-funded sites are added. For those below poverty level, the proportions are 20.2% and 1.9%, respectively. Several US regions, including the South and Appalachia, have particularly limited access to NCI-funded sites despite high cancer incidence, and much of the West and Great Plains are distant from any cancer facilities. Conclusions: NCI could address travel distance as a major barrier to research participation by expanding the geographical footprint of its infrastructure funding using existing institutions in areas with identified gaps. Geospatial analysis at the census tract level is recommended and geospatial visualization can help identify strategic areas for interventions.