For this study, unfavorable intermediate risk prostate cancer patients will select whether they are to be treated with the standard of care (SOC) 6 months of Androgen Deprivation Therapy (ADT) in conjunction with stereotactic body radiation therapy/radiosurgery (SBRT) directed to the prostate versus SBRT alone. The patient population will include those with National Comprehensive Cancer Network (NCCN)-defined unfavorable intermediate risk disease. All patients will be followed every 6 months for up to 5 years from the first patient treated and will undergo a routine 24-30 months post-SBRT prostate biopsy to assess for local tumor control.

Inclusion Criteria:

• Biopsy proven unfavorable intermediate risk prostate cancer, which includes patients with any one of the following variables: Gleason 4+3 disease; Percent positive cores > 50% of Gleason 7 disease; 2-3 intermediate risk factors (Gleason 7; PSA 10-20 ng/mL; or T2b-T2c)
• Patients must have tissue available for Decipher score testing. Results must be available before start of treatment.
• Serum testosterone ≥ 150 ng/dL determined within 2 months prior to enrollment
• At least 4 weeks must have elapsed from major surgery
• Karnofsky Performance Scale (KPS) ≥ 80%
• Prostate size as determined on MRI to be < 90 cc. Prostate size can be determined on CT scan if MRI is not available
• IPSS ≤ 20
• Patient must be available for follow-up. After 2 years of follow-up, upon completion of post-treatment biopsy, telephone and chart review-based follow-up will be acceptable
• Adequate hepatic function with serum bilirubin less than or equal to 1.5 times the upper institutional limits of normal (ULN), Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) less than or equal to 2.5 x ULN. Patients with a history of Gilbert's syndrome may be enrolled if the total bilirubin is < 3 mg/dL with a predominance of indirect bilirubin
• Adequate renal function with serum creatinine less than or equal to 1.5 x ULN
• Adequate hematologic function with absolute neutrophil counts of at least 1,500 cell/mm3 and platelets of at least 100,000 cells/mm3 and hemoglobin value > 9 g/dL (Note: patients whose anemia has been corrected to a hemoglobin value > 9 g/dL with blood transfusions are allowed).

Exclusion Criteria:

• CT or MRI or Positron Emission Tomography (PET) scan evidence of metastatic disease to the bone
• Patients with one or more positive lymph nodes considered suspicious as determined by clinical assessment on MRI or CT or PET scan
• Prior treatment for prostate cancer, including history of chemotherapy, hormonal therapy within 30 days of enrollment or surgery for prostate cancer (except for prior (transurethral resection of prostate) TURP or greenlight (photoselective vaporization of prostate) PVP which would be allowed)
• History of another malignancy within the previous 2 years except for the following: adequately treated basal cell or squamous cell skin cancer, superficial bladder cancer, currently in complete remission, or any other cancer that has been in complete remission for at least 3 years
• Patients with Crohn's disease or ulcerative colitis

De-identified IPD access will be limited to study team members who are IRB approved and listed on the delegation log.