Initial treatment and resource utilization among patients with metastatic-castration sensitive prostate cancer in Japan: a retrospective real-world study

Objectives The introduction of novel drugs for metastatic castration-sensitive prostate cancer has expanded treatment options for patients. Associated changes in healthcare resource utilization may have occurred in tandem, but nationwide information is limited. This study aimed to describe initial treatment patterns and healthcare resource utilization (including costs) for patients with metastatic castration-sensitive prostate cancer in routine clinical practice in Japan.Methods This retrospective, longitudinal cohort study used a large-scale claims database covering acute care hospitals of various sizes. Included were men who received first medical treatment for metastatic castration-sensitive prostate cancer between January 2015 and July 2021 (identification period). The primary endpoint was the initial treatment pattern for metastatic castration-sensitive prostate cancer.Results Among 7665 men with metastatic castration-sensitive prostate cancer, the median (Q1, Q3) duration of first-line therapy was 8.2 (3.4, 17.3) months. During the overall period between 2015 and 2021, the most common initial pharmacotherapy (88.1% of treatment regimens) was 'combined androgen blockade or androgen deprivation therapy only or first-generation anti-androgen only'. Use of androgen receptor signaling inhibitors increased following their introduction in 2018, reaching 26.6% of treatments started in 2021 (abiraterone + androgen deprivation therapy 9.4%, apalutamide + androgen deprivation therapy 9.2%, enzalutamide + androgen deprivation therapy 8.0%). Median total healthcare-related cost per person-year was JPY 244 479, with metastatic castration-sensitive prostate cancer drugs accounting for approximately one-third of the cost (JPY 396 620).Conclusions Since androgen receptor signaling inhibitors were introduced, treatment patterns in patients with metastatic castration-sensitive prostate cancer in Japan have shifted, with an increased trend toward prescription of these agents. However, the most frequently used regimen for first-line treatment continues to be 'combined androgen blockade or androgen deprivation therapy only or first-generation anti-androgen only'. A real-world database analysis showed that, while prescription of androgen receptor signaling inhibitors has increased, combined androgen blockade or androgen deprivation therapy remains the most common regimen for initial treatment of metastatic castration-sensitive prostate cancer patients in Japan.