Study of PSMA PET/MR Guided Stereotactic Body Radiation Therapy With Simultaneous Integrated Boost (SBRT-SIB) for High-Intermediate and High Risk Prostate Cancer

This is a single-arm Phase II clinical trial assessing the clinical efficacy of prostate specific membrane antigen (PSMA) PET/MR guided MR-LINAC based SBRT-SIB with planned accrual of 50 patients.

Localized prostate cancer can be treated in 5 sessions using a precise, targeted form of radiation known as stereotactic body radiation therapy (SBRT), with low toxicity. Despite these advances, overall outcomes for aggressive (high risk) prostate cancer remain poor, with 10-year recurrence-free survival of approximately 65% regardless of treatment modality. Recurrences are typically distant and carry poor prognosis, with 5 year survival of 25%. The investigators propose to utilize the latest advances in cancer imaging (PSMA Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MR)) and radiation delivery (MR-guided radiation therapy with real-time adaptive planning), to deliver a personalized radiation treatment that targets the areas of greatest risk of recurrence in the prostate with improved precision, and as a result improve clinical outcomes for individuals with high risk prostate cancer. PSMA PET/MR is a novel imaging modality, not yet widely available, that augments the tissue detail provided by MR. The combination of PSMA PET with MR results in improved delineation of intraprostatic nodules and higher diagnostic accuracy for detection of metastatic disease compared to conventional imaging. PSMA PET/MR imaging data is readily transferable to a MR-based linear accelerator (MR-LINAC), a novel, innovative platform that allows direct visualization of the tumor during treatment, and permits real-time individualized correction for motion with online adaptive radiation planning.

Eligibility Criteria:
Inclusion Criteria:

* Male aged 21 years or older.
* Ability to provide signed informed consent and willingness to comply with protocol requirements.
* Pathologic confirmation of high-risk adenocarcinoma of the prostate gland as follows: a. Gleason 8-10 or tertiary component 5 disease and/or b. PSA of 20 ng/ml or greater and/or c. Tumor stage of T2c or greater; OR Unfavorable intermediate risk (Gleason 4+3=7, \>50% of cores involved, or 2 or more intermediate risk factors which include Gleason 7 disease, PSA 10-20, or T2b disease)
* Participants must agree to use an acceptable form of birth control and utilize condoms for a period of seven days after each PSMA injection, if engaged in sexual activity.
* No evidence of metastatic disease, including pelvic lymph nodes.

Exclusion Criteria:

* Clinical and/or technical factors that would compromise statistical analysis of the PET and/or MR.
* Contraindications to PSMA IV administration
* Contraindications to prostate SBRT (history of transurethral resection of prostate; prostate size greater than 150 cc; AUA score greater than 20; history of prior radiation to the prostate)
* Other unspecified reasons that, in the opinion of investigators, make the subject unsuitable for enrollment
* Patients on or intending to take abiraterone will be excluded