Stereotactic Body Radiotherapy for Stage I-III Prostate Cancer

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