Modeling the Structural Relationships between Travel Distance, Built Environment, and Cancer Outcomes

The centralization of cancer treatment centers in large cities results in transportation-related barriers to accessing high-quality cancer care. Although evidence suggests limited access and long-distance treatments negatively affect cancer outcomes, the literature remains uncertain about the effect of built environment attributes on treatment consequences. This study examines the effects of geographical accessibility and built environment attributes on improved cancer outcomes. A cross-sectional survey of cancer patients in the United States (2019) was conducted to collect data related to those patients who received radiotherapy and chemotherapy treatments, including their travel-related patterns to health care providers. We employed geographic information systems (GIS) to geocode patients’ home and healthcare provider locations to identify travel distance to care providers. In addition, the residential built environment attributes, including density, diversity, distance to transit, and street design, have been measured. To explore the research assumptions, we employed structural equation models (SEMs) and tested the effects from key variables on cancer outcomes as well as interaction effects among the posited variables. Results from the SEM indicate that patients living in neighborhoods with long distances to transit and the long distance to the closest hospital are more likely to have longer travel distances to radiotherapy providers as well. Moreover, as the travel distance to radiotherapy providers increases, the frequency of radiotherapy trips reduces. However, long travel distance to radiotherapy providers is positively associated with greater tumor-free years. For chemotherapy, travel distance to the closest large hospital increases travel distance to the chemotherapy provider, however, neither built environmental measures nor travel distance significantly affects tumor-free years. Only travel frequency to chemotherapy providers slightly increases the tumor-free years for cancer. Thus, traveling the remoter distance to radio providers may enhance the opportunity of access to higher volume hospitals with advanced treatment quality and surpass the potential downsides of longer travel distance. The results have great potential to help policymakers and urban planners make informed decisions on how designing-built environment to enhance equity access to cancer treatments and improve patients’ health outcomes.