To determine the comparative effectiveness of primary radical prostatectomy (RP) compared to external bean radiation therapy (EBRT) with androgen deprivation therapy (ADT), or EBRT plus brachytherapy (BT) with or without ADT among Medicare fee-for-service beneficiaries with high-risk prostate cancer, for 10-year, mortality (overall and prostate cancer-specific), complications, health service use, and cost.