Stereotactic Body Radiation Therapy in Treating Patients With Low- and Intermediate-Risk Prostate Cancer

PRIMARY OBJECTIVES: I. To evaluate, in terms of late toxicity, the safety of stereotactic radiation therapy using the proposed fractionation schedule. SECONDARY OBJECTIVES: I. To evaluate, in terms of acute toxicity, the safety of stereotactic radiation therapy using the proposed fractionation schedule. II. To determine stereotactic treatment efficacy through biochemical failure (Phoenix criteria). III. To determine the protocol completion rate. IV. To describe patient-reported outcomes using International Index of Erectile Function (IIEF) and EPIC Urinary and Bowel Assessment questionnaires. OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM I: Patients undergo standard daily fractions of stereotactic body radiation therapy (SBRT) over 7-8.5 weeks.