A Study of Stereotactic Body Radiation Therapy (SBRT) Without Androgen Deprivation Therapy (ADT) in People With Unfavorable Intermediate-Risk Prostate Cancer

Inclusion Criteria: * Pathologically proven diagnosis of prostate adenocarcinoma within 12 months of enrollment * Unfavorable intermediate risk prostate cancer by NCCN 2021 risk stratification guidelines, including any of the following clinicopathologic features: * Gleason Score 4+3 * ≥ 50% biopsy cores positive * Two or more of the following risk factors: * Grade Group 2 or 3 * cT2b-T2c * PSA 10 - 20 ng/mL * Able to undergo MRI for initial staging and MR based radiation planning * Sufficient biopsy tissue available for Decipher genomic testing * Prostate volume \< 90cc * IPSS ≤ 20 * Age ≥ 18 * KPS ≥ or ECOG 0-2 * Estimated life expectancy \>5 years * Willing and able to provide written informed consent and Authorization for Use and Release of Health and Research Study Information (HIPAA authorization) Exclusion Criteria: * Radiographic T3-T4 detected on staging mpMRI °Must be "consistent with" (\>90% probability) or suspicious for/probable/probably (75%-90% probability) ofT3-T4 disease determined by the reading radiologist. * Evidence of distant metastases as determined by MRI, PET, or CT imaging * Evidence of pelvic lymph node involvement as determined by MRI, PET, or CT imaging * Prior treatment for prostate cancer including chemotherapy, surgery, or hormonal therapy * Prior pelvic radiation * Active second malignancy or past history of malignancies diagnosed within the last 2 years that requires active therapy and/or in remission, with the exception of resected non-melanoma skin cancers, non-muscle invasive bladder cancer, stage I head and neck cancer, or stage I colorectal cancer * TURP or greenlight PVP within 6 months of enrollment * History of Crohn's Disease or Ulcerative Colitis