Risk Stratified De-escalated Hormone Therapy With Radiation Therapy for the Treatment of Prostate Cancer

This phase II trial tests how well risk based de-escalated hormone therapy (i.e., fewer treatments) with radiation works in treating patients with prostate cancer. Androgen deprivation therapy (ADT), such as gonadotropin-releasing hormone analogs (LHRH) and abiraterone acetate (Zytiga), lower the amount of the male hormone, testosterone, made by the body. This may help kill or stop the growth of tumor cells that need testosterone to grow. Radiation therapy uses high energy x-rays, particles, or radioactive seeds to kill cancer cells and shrink tumors. Research has shown that long-term ADT is beneficial for patients with high-risk prostate cancer. However, there are few studies that determine ADT treatment based on risk factors. Giving risk based de-escalated ADT with radiation therapy may be as effective as giving more ADT in treating high-risk prostate cancer.

PRIMARY OBJECTIVE: I. Recovery of the Expanded Prostate Cancer Index Composite (EPIC) hormonal domain to baseline levels at 2-years. EXPLORATORY OBJECTIVES: I. After completion of radiation therapy, determine the incidence of: Ia. Grade 2 or greater genitourinary (GU) and gastrointestinal (GI) toxicity at 6 months (Common Terminology Criteria for Adverse Events \[CTCAE\] version 5.0); Ib. Grade 3 or greater GU and GI toxicity at 6 months (CTCAE version 5.0); Ic. Patient-reported quality of life; Id. Impotence after the use of radiation therapy at 3 years; Ie. Freedom from biochemical failure (FFBF) at 5 years; If. Clinical failure: local and/or distant at 5 years; Ig. Salvage androgen deprivation use (SAD) at 5 years; Ih. Progression free survival: using clinical, biochemical and SAD as events at 5 years; Ij. Overall survival at 5 years; Ik. Disease-specific survival at 5 years. II. Determine overall GI and GU toxicity. OUTLINE: Patients are assigned to 1 of 3 risk groups. GROUP I (LOW RISK): Patients undergo radiation therapy to the prostate bed over 2 - 6 weeks. GROUP II (INTERMEDIATE RISK): Patients receive ADT subcutaneously (SC) or intramuscularly (IM) for up to 12 months in the absence of disease progression or unacceptable toxicity. Patients also undergo radiation therapy to the prostate bed over 2 - 6 weeks starting on week 8-10 of ADT hormone therapy. GROUP III: (HIGH RISK): Patients receive ADT SC or IM with or without abiraterone acetate for up to 18 months in the absence of disease progression or unacceptable toxicity. Patients also undergo radiation therapy to identified areas over 2 - 6 weeks starting on week 8-10 of ADT hormone therapy. Additionally, patients undergo positron emission tomography (PET), computed tomography (CT) or magnetic resonance imaging (MRI), and blood sample collection throughout the trial. After completion of study treatment, patients are followed up at months 3 and 12, then yearly for up to year 5 followed by every 2 years.