Fig. 6

Kaplan-Meier curves for progression-free survival. The median progression-free survival was 6.1 months (95% confidence interval [CI], 4.7–7.8) for PE and 4.9 months (95% CI 3.2–6.4) for PA (HR 0.55, 95%CI, 0.41–0.75; p = 0.001). *The hazard ratio was calculated using a Cox proportional hazards model, with the age, time since diagnosis, PSA level, alkaline phosphatase level, clinical stage at diagnosis, pathological stage at diagnosis, Gleason sum at diagnosis, mCRPC-related brain metastasis, ECOG status, and number of metastatic sites used as covariates and therapy as the time-dependent factor