Cancer-Control Outcomes of Japanese Vs. German Metastatic Hormone-Sensitive Prostate Cancer Patients: A Real-World Cross-Country Comparison of Patients Undergoing Combination Therapies.

OBJECTIVES: Differences in tumor biology, ethnicities, and healthcare structures across populations may contribute to variability in oncologic outcomes. This study compared baseline characteristics and oncologic outcomes of Japanese and German metastatic hormone-sensitive prostate cancer (mHSPC) patients. METHODS: A pooled analysis of 1 215 mHSPC patients from Japan (JIKEI-YAYOI database, n = 639) and Germany (FRAMCAP database, n = 576) undergoing combination therapies between 2015 and 2025 was performed. Cox regression models were used to evaluate time to castration-resistant prostate cancer (ttCRPC) and overall survival (OS). Propensity score matched analyses (PSM) validation was performed. RESULTS: Japanese patients were older at diagnosis (median 73 vs. 70 years) and had higher PSA at mHSPC diagnosis (260 vs. 43 ng/mL). Moreover, Japanese patients had more frequently synchronous mHSPC (95% vs. 75%), high-volume disease (78% vs. 54%), and visceral metastases (16% vs. 8%). ADT plus androgen receptor pathway inhibitors (ARPI) was used more frequently in Japan (76% vs. 71%), as was the combination of ADT + ARPI + docetaxel (17% vs. 11%). Conversely, ADT + docetaxel was less commonly used in Japan (7% vs. 19%). Median ttCRPC was 39 vs. 23 months, and median OS was 80 vs. 51 months (Japan vs. Germany). After adjustment for relevant clinical covariates, Japanese cohort affiliation remained an independent predictor of prolonged ttCRPC (HR 0.53, p < 0.001) and improved OS (HR 0.54, p < 0.001). PSM analyses confirmed similar findings. CONCLUSIONS: Despite presenting with more adverse baseline characteristics, Japanese mHSPC patients demonstrated longer ttCRPC and improved OS compared with patients in Germany. These differences may reflect not only potential biological variations but also differences in treatment strategies and healthcare structures. TRIAL REGISTRATION: Not applicable.