Regional disparities in pediatric radiotherapy utilization in Japan: analysis of a nationwide database

Pediatric radiotherapy (RT) plays a key role in childhood cancer care, yet regional disparities in its utilization and delivery persist. We aimed to quantify prefecture-level disparities in pediatric RT utilization and examine associations with workforce and facility factors.

Using the Ministry of Health, Labour and Welfare National Database Open Data, we extracted counts of pediatric RT add-on claims (fractions) for fiscal year 2023. Utilization was calculated as claims per 100,000 children (< 15 years). Explanatory variables were the number of board-certified pediatricians and the presence of a designated pediatric cancer hub hospital in each prefecture. We conducted Pearson/Spearman correlation analyses and Welch's t-test, reporting Cohen's d. Supplementary analyses summarized prefecture-level distributions and 5-year trends (2019-2023).

The national mean utilization was 58.7 fractions per 100,000 children (range, 0.0-161.0), with marked inter-prefectural variability. Pediatrician numbers strongly correlated with claim counts (r = 0.94, p < 0.001) but not with claims per 100,000 children (r = 0.18, p = 0.22). Prefectures with a pediatric cancer hub hospital had significantly higher utilization than those without (80.9 vs. 50.2 per 100,000; p = 0.046), with Cohen's d = 0.66. In a multi-year view, several prefectures (e.g., Mie, Miyagi, Tokyo) repeatedly maintained higher utilization.

This study examined prefecture-level disparities in pediatric radiotherapy across Japan. The number of board-certified pediatricians was associated with crude treatment counts but not with population-normalized rates, whereas prefectures with a designated pediatric cancer hub hospital showed significantly higher rates. These findings can inform policy making and healthcare resource allocation, particularly efforts to strengthen hub hospitals and cross-prefectural referral networks.