In France, while radiotherapy is primarily covered by national health insurance, disparities in access may persist. These disparities can be influenced by geographic location, leading to variations in travel time to the nearest radiotherapy unit, the number of accessible radiotherapy units within a reasonable commute, the availability of specific treatments such as brachytherapy, and the resource density within accessible radiotherapy units. This study aimed to assess the accessibility and availability of radiotherapy across France, identifying potential inequities among the population based on home location and regional mean income.

The study covered metropolitan France (including Corsica) and the French overseas departments/territories of Guadeloupe, Martinique, and Réunion, using the commune (municipality) and Paris/Marseille/Lyon arrondissements (city districts; treated as separate communes ) as the geographic unit. For each department, annual sex-specific cancer incidence (2007–2014) was applied proportionally to commune populations to estimate the number of patients undergoing radiotherapy, with the scaling coefficient derived from France-wide radiotherapy volumes in 2022. Geographic accessibility was quantified by calculating road and public-transport travel times from each commune 's main city to all radiotherapy units, using Haversine-based candidate selection (up to 70 km, extended to 100 km) and Google Maps/La Poste (French postal service) validation; a radiotherapy unit was considered accessible for external beam radiotherapy, stereotactic body radiotherapy, and brachytherapy if best transportation time was less than 45 min, 60 min, and 90 min, respectively. Availability was summarized using population-weighted efficiency (mean) and equity (dispersion via SD/IQR/D9/D1) across communes , with commune -level availability metrics derived from accessible radiotherapy units (averaged when multiple were accessible; otherwise from the closest), and no statistical testing performed because all French communes were analysed.

Ninety percent of the study population had access to at least one radiotherapy unit within 45 min of travel (one-way). Forty percent had access by public transportation within 45 min. Two-thirds had access to at least two radiotherapy units within 45 min. Excluding head and neck brachytherapy, 40 % of the population had access to all treatment modalities (external beam radiotherapy, stereotactic body radiotherapy, and all types of brachytherapy). Residents of mountainous and less densely populated areas faced longer travel times to the nearest radiotherapy unit. The availability of resources within the closest radiotherapy unit was independent of travel time, territorial population density, and mean regional income. In dense territories, accessibility was similar regardless of regional mean income; however, in non-dense territories, accessibility was higher in areas with higher incomes.

Despite generally good and equitable access in France, disparities persist that may be attributed to factors beyond the control of healthcare authorities, such as territorial density, mountainous terrain, and potentially the real estate market. Densely populated areas offer both the highest and most equitable accessibility to radiotherapy.