Focal Therapy With Stereotactic Body Radiation Therapy (SBRT) for Patients With a Single Prostate Tumor

Inclusion criteria

• Participants must have histologically confirmed, low or intermediate risk prostatic adenocarcinoma verified by biopsy (NIH Laboratory of Pathology confirmation is required).
• Unifocal prostate cancer defined as a single focus of prostate cancer on MRI and PSMA PET/CT imaging which is correlated with a positive targeted biopsy.
• Age \>=18 years.
• ECOG performance status \<=2 (Karnofsky \>60%).
• Men must agree to use highly effective contraception with their partner (barrier method of birth control; abstinence) for the duration of study participation and up to 120 days after the last radiation treatment.
• Ability of individual to understand and the willingness to sign a written informed consent document.

Exclusion criteria

• Participants with NCCN high-risk prostate cancer features (Gleason score \>=8, \>cT2c, or PSA \>= 20 ng/mL).
• Participants with prostate biopsies which show \>= grade group 2 adenocarcinoma determined to be outside of the radiographically visible lesion (systematic biopsies which map to a radiographically detected lesion are not an exclusion criterion).
• Participants in whom concurrent systemic Androgen Deprivation Therapy (ADT) or chemotherapy is planned.
• Participants who are receiving any other investigational agents.
• Participants found to have pelvic or distant metastases on pre-treatment staging studies.
• Participants with an AUA-SI/IPSS score \> 18.
• Participants who have previously received curative treatment for a prior or the current diagnosis of prostate cancer.
• Active urinary tract infection assessed by urinalysis.
• Human immunodeficiency virus (HIV)-infected individuals who are not on effective anti-retroviral therapy. Participants on anti-retroviral therapy with undetectable viral load within the 6 months prior to registration are eligible for this trial.
• Participants with hepatitis B virus (HBV) infection who have not been treated and cured.
• Participants with chronic HBV at screening must have an undetectable HBV viral load on suppressive therapy.
• Participants with hepatitis C virus (HCV) infection who have not been treated and cured.
• Participants with HCV infection who are currently on treatment, are eligible if they have an undetectable HCV viral load at screening.
• Anatomic relationship between the tumor and adjacent normal tissues judged to be unfeasible for the planned treatment by the PI.
• Participants with connective tissue diseases.
• Participants with radiation hypersensitivity syndromes.
• Ongoing active inflammatory bowel disease within the radiation field.
• Participants with prior medical comorbidity or surgical history involving the low pelvis which is expected to confer a high risk of toxicity to the experimental radiation regimen.
• Ineligibility or unwillingness to undergo a contrast-enhanced MRI due to inadequate renal function (eGFR \< 30), severe claustrophobia, a weight above tolerance of the scanner (\> 350 lbs.), a body size unable to fit into the scanner, or implanted devices incompatible with an MRI (implanted cardiac devices, surgical hardware, retained shrapnel, cerebral aneurysm clips, or other incompatible objects.
• Unwillingness to undergo an 18F-DCFPyL PET/CT or known allergy to the 18F-DCFPyL tracer.
• Contraindication or inability to undergo fiducial marker implantation.
• History of prior radiotherapy overlapping with the intended radiation field.
• Uncontrolled intercurrent illness, factors, or social situations that would limit compliance with study requirements.