Geographic Accessibility of Radiation Therapy Facilities in Sub-Saharan Africa

Purpose: Access to radiation therapy in Sub-Saharan Africa (SSA) remains unacceptably low. Prior studies have focused on how many radiation therapy machines a country has but have not accounted for geographic accessibility, which is a known barrier to radiation therapy compliance. In this study, we describe accessibility measured as travel time by road to radiation therapy in SSA.

Methods and materials: This study used geographic information systems modeling techniques. A list of radiation therapy facilities was obtained from the Directory of Radiotherapy Centres. We obtained a 1 km² surface of travel times using a least-cost-path algorithm implemented in Google Earth Engine (Google, Mountain View, CA). AccessMod 5 (World Health Organization, Geneva, Switzerland) was used to compute the percentage of each country's population with access to a radiation therapy facility within prespecified one-way travel time intervals. We then ranked countries using 3 measures of access: 2-hour geographic access, units per capita, and units per cancer case.

Results: Only 24.4% of the population of SSA can access a radiation therapy facility within 2 hours of travel by road; access was 14.6% and 42.5% within 1 and 4 hours, respectively. More than 80% of Rwandans and South Africans were within 2 hours of radiation therapy, the highest in the region. Although countries with more radiation therapy units per capita tended to have higher 2-hour access, there was notable discordance between the 2 measures. Mauritania, Zambia, Sudan, and Namibia were among the top 10 countries ranked by machines per capita, but none ranked in the top 10 by 2-hour geographic access. There was similar discordance between 2-hour access and radiation therapy units per cancer case; Rwanda, Nigeria, Senegal, and Cote d'Ivoire ranked in the top 10 for the former but ranked worse using units per cancer case.

Conclusions: Prior measures of radiation therapy access provide an incomplete picture. Geographic location of radiation therapy centers is a crucial component of access that should be considered for future planning in SSA.