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