Conventional or Hypofractionated Radiation Therapy in Treating Patients With Prostate Cancer

PRIMARY OBJECTIVE: I. To assess the gastrointestinal (GI) and genitourinary (GU) toxicities in patients treated with hypo-fractionated postoperative radiotherapy relative to the conventional postoperative radiotherapy. SECONDARY OBJECTIVES: I. To report patient outcome to include local control, loco-regional control, distant metastases, biochemical progression-free survival, prostate-cancer specific survival (PCSS), time to salvage therapy. Ia. To compare freedom from biochemical failure (FFBF) and time to progression (TTP) with definition of post prostatectomy nadir + 2 ng/mL in both treatment arms. II. To evaluate patient reported quality of life outcomes with hypo-fractionated compared to standard fractionated postoperative radiotherapy using validated surveys (Expanded Prostate Cancer Index Composite \[EPIC\]-26, Short Form \[SF\]-12, EuroQol 5 dimensional \[EQ-5D\]) and use of erectile dysfunction medications/devices. III. To compare patient reported GU symptoms using the Common Terminology Criteria for Adverse Events (CTCAE) version 5 (specifically GU symptoms) and quality of life reports with EPIC-26, SF-12, EQ-5D survey at end of radiation therapy (RT), 6, 12, 24 and up to 60 months from the end of radiation therapy. IV. To compare patient reported GI symptoms using CTCAE version 5 (specifically GI symptoms) and quality of life reports with the EPIC-26 SF-12, EQ-5D survey at end of RT, 6, 12, 24, and up to 60 months from the end of radiation therapy. V. To report health economics with cost and time based driven activity (TDABC) in delivering shorter hypofractionated courses of radiotherapy compared to standard course (indirect and direct cost). OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients undergo conventional radiation therapy daily over 7 weeks after standard of care surgery. ARM II: Patients undergo hypofractionated radiation therapy over 4.5 weeks after standard of care surgery. After completion of study treatment, patients are followed up at 3-6 months, and then every 6-12 months for up to 5 years.