Radiation Therapy in Treating Patients With Prostate Cancer

RATIONALE: Radiation therapy uses high-energy x-rays to kill tumor cells. Specialized radiation therapy that delivers a high dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue. Given radiation therapy in different ways may kill more tumor cells. PURPOSE: This randomized phase II trial studies radiation therapy to see how well it works in treating patients with prostate cancer.

OBJECTIVES: Primary * To demonstrate that 1-year health-related quality of life (HRQOL) for at least one hypofractionated arm is not significantly lower than baseline as measured by the Bowel and Urinary domains of the Expanded Prostate Cancer Index Composite (EPIC) instrument. Secondary * To estimate the degree of change in HRQOL in each arm for the Sexual and Hormonal EPIC domains and the Utilization of Sexual Medications/Devices from baseline to 1 year, 2 years, and 5 years. * To estimate the degree of change in global HRQOL in each arm as measured by the Euro Quality of Life, 5 dimensions (EQ-5D) from baseline to 1 year, 2 years, and 5 years. * To estimate the rate of acute and late gastrointestinal (GI) and genitourinary (GU) toxicity for each arm at 1, 2, and 5 years. * To estimate prostate-specific antigen (PSA) failure in each arm at 1, 2, and 5 years. * To estimate disease-free survival (DFS) in each arm at 1, 2, and 5 years. * To estimate Quality Adjusted Life Years for each arm at 1, 2, and 5 years using the EQ-5D and DFS. * To identify genetic markers associated with normal tissue toxicities resulting from radiotherapy. * To collect tumor tissue for biomarker studies. * To estimate EPIC bowel and urinary HRQOL as continuous variables. OUTLINE: This is a multicenter study. Patients are stratified according to treatment techniques/machine (all linear accelerator-based treatment \[excluding cyberknife\] vs cyberknife vs protons). Patients are randomized to 1 of 2 treatment arms. * Arm I: Patients undergo hypofractionated radiotherapy using intensity-modulated radiation therapy (IMRT), cyberknife, or protons twice a week for approximately 2½ weeks (36.25 Gy total). * Arm II: Patients undergo hypofractionated radiotherapy using IMRT, cyberknife, or protons once a day, 5 days a week, for approximately 2½ weeks (51.6 Gy total). Patients may undergo blood and tumor tissue collection for correlative studies. Patients may also complete the Utilization of Sexual Medications/Devices, the European Questionnaire-5D, and the Bowel and Urinary domains of the Expanded Prostate Cancer Index Composite (EPIC) questionnaires at baseline and at 1, 2, and 5 years after completion of radiation therapy. After completion of study therapy, patients are followed-up every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.