A high-resolution geospatial analysis of radiation therapy access in the Philippines

In 2019, the Philippines enacted the National Integrated Cancer Control Act (NICCA) to decentralise cancer care. However, implementation remains limited by a lack of data to guide effective resource allocation. This study provides high-resolution, quantitative baseline data of radiotherapy (RT) accessibility in Luzon, the country's largest island group, to identify priority areas for infrastructure development.

A cross-sectional geospatial analysis for 698 municipalities was conducted using the Enhanced Two-Step Floating Catchment Area (E2SFCA) model, integrating provider capacity, population demand and calibrated travel time. Access was modelled under two scenarios: one including all 43 RT facilities and another restricted to the 12 public centres. To quantify financial toxicity, we developed a novel metric, the travel-cost-to-wage ratio. We performed spatial autocorrelation and multivariable regression analyses to identify geographic clusters and key determinants of access.

Profound inequities in RT access were identified. Considering all facilities, 240 municipalities (34.4%) home to 7.5 million people, had no potential access within a 120-minute catchment. The public-only scenario revealed a near-total system inadequacy, with 12.2 million people lacking access. Spatial analysis confirmed a stark core-periphery pattern, with a well-served core centred around the national capital and along the primary north-south expressway network, contrasted with vast, statistically significant 'RT deserts' in outlying regions. For 4.9 million people, a single round-trip to the nearest public facility costs more than a day's minimum wage; this travel-cost-to-wage ratio was the strongest predictor of access (odds ratio = 0.83, p < 0.001).

Spatial access to RT in Luzon is profoundly inequitable, characterised by a stark core-periphery pattern and an inadequate public system that leaves millions reliant on private care or entirely without access. This study provides a data-driven roadmap to guide the strategic implementation of NICCA, ensuring that future resource allocation targets the identified RT deserts to address these critical gaps in cancer care.