Prognostic factors in Japanese men with high-Gleason metastatic castration-resistant prostate cancer.

Background: Several therapeutic agents are available for metastatic castration-resistant prostate cancer (CRPC). However, prognosis is still not well developed. The Gleason score (GS) is a prognostic factor available for patients with metastatic CRPC. GSs ranging from 6 to 10 and GSs ≥8 are usually categorized as single prognostic factors. In this study, we evaluated the prognosis of high-GS metastatic CRPC in Japanese men. Methods: Overall, 105 patients with metastatic CRPC with a GS ≥8 were retrospectively analyzed. Multivariate analyses of patient age, GS, and Eastern Cooperative Oncology Group performance status (ECOG-PS) were performed using Cox proportional hazards analysis to predict overall survival (OS). Results: GS 8 had all Gleason patterns of 4+4. Thirty patients (28.6%) had GS of 8, and 75 (71.4%) had GS of 9 or 10. As a first-line treatment for metastatic CRPC, 42 patients (40%) received abiraterone, 35 (33.3%) received enzalutamide, and 26 (24.8%) received docetaxel. The 5-year OS in patients with GS of 8 was 65.0% [95% confidence interval (CI): 43.07-86.82%], while the 5-year OS in patients with GS of 9 or 10 was 37.0% (95% CI: 24.41-56.11%). There was a significant difference in OS between the GS 8 and GS 9-10 groups (log-rank test, P=0.038). Multivariate analysis showed that GS and ECOG-PS were significant prognostic factors for OS. Conclusions: Patients with metastatic CRPC with GS 9-10 had poor prognoses, suggesting the need for additional treatment options.