Inclusion Criteria:

          -  Histologically proven prostate adenocarcinoma

          -  Clinical stage T1a-T3, N0-Nx, M0-Mx

          -  Patients belonging in one of the following risk groups: (1) LOW RISK: CS T1a-T2a,
             Gleason 2-6, PSA<10, Nx-0, Mx-0; (2) INTERMEDIATE RISK: CS T2b, Gleason ≤7, PSA<20,
             Nx-0, Mx-0, or CS T1a-T2b, Gleason 2-6, PSA≥10 & <20, Nx-0, Mx-0, or CS T1a-T2b,
             Gleason 7, PSA≤20, Nx-0, Mx-0; or (3) HIGH RISK: CS T2c-T3, any Gleason, any PSA, or
             CS T1-3, Gleason ≥8 and/or PSA≥20

          -  Karnofsky performance status 70-100

          -  Hormone therapy: includes LHRH agonists (e.g. leuprolide, goserelin, triptorelin),
             antagonists (e.g. degarelix), peripheral blockers (e.g. flutamide, bicalutamide,
             nilutamide), estrogens (e.g. DES) and bilateral orchiectomy

          -  Low and Intermediate risk groups: no hormone ablation for two months prior to
             enrollment, or during treatment

          -  High risk group: three hormone therapy regimens are allowed

          -  5-alpha reductase inhibitors (e.g., finasteride or dutasteride) are allowed

        Exclusion Criteria:

          -  Prior prostatectomy or cryotherapy of the prostate

          -  Prior high-dose radiotherapy to the prostate or lower pelvis

          -  Implanted hardware or other material that would prohibit appropriate treatment
             planning or treatment delivery, in the investigator's opinion