Regional differences in epidermal growth factor receptor-tyrosine kinase inhibitor therapy in lung cancer treatment using a national database in Japan

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are extensively used in the treatment of non-small cell lung cancer (NSCLC); hence, equal access to them is important. Therefore, this study aimed to identify regional differences in the prescription of EGFR-TKIs and the factors contributing to these differences. In this ecological study, we collected data using the National Database Open Data and the National Cancer Registry. The standardized claim ratio (SCR) was used as an indicator of the number of EGFR-TKI prescriptions. Additionally, we examined the association between SCR and various factors to identify the factors associated with this difference. The average SCR for the top three provinces was 153.4, while the average for the bottom three provinces was 61.6. Multivariate analysis used for evaluating the association of SCR with variables revealed that the number of designated cancer hospitals and radiation therapies were independent factors associated with the SCR of EGFR-TKIs. There were significant regional differences in the prescriptions of EGFR-TKIs in Japan based on the number of coordinated designated cancer hospitals and the number of patients receiving radiotherapy alone. These findings emphasize the need to implement policies to increase the number of hospitals to reduce regional differences.