Analysis of Medical Costs of Melanoma Using a Japanese National Database

The advent of immune checkpoint inhibitors (ICIs) and targeted therapeutic agents (TTAs) has improved melanoma treatment. With the ongoing development of novel drugs, treatment options are expected to expand further. However, this is also anticipated to increase the financial burden on patients. Changes in medical costs for melanoma patients have not yet been examined in Japan. Therefore, we herein conducted a retrospective observational study using data from a Japanese nationwide database. The dataset comprised 14 727 patients diagnosed with melanoma between April 2008 and June 2023. The mean monthly cost per patient was calculated and changes were evaluated. The results obtained showed that the mean monthly cost per patient has consistently increased, and a breakdown revealed that drug costs for ICIs and TTAs accounted for a significant percentage of these costs. Furthermore, the usage rates of ICIs and TTAs have steadily increased since their approval in 2014, with a notable rise being observed in 2018 when adjuvant therapies were approved in Japan. An interrupted time series analysis further confirmed a significant increase in medical costs around 2018. While ICIs and TTAs represent major advances in melanoma treatment, their increasing use underscores the need for a careful evaluation of both clinical benefits and economic sustainability.