PSMA PET Response Guided SabR in High Risk Pca

Eligibility Criteria

• * Planned for definitive intent stereotactic ablative radiotherapy (SabR) with integrated dose boost to intra-prostatic tumor and androgen deprivation therapy (ADT) with baseline AUA IPSS \<=18 and prostate size \<=100cc
• * Staging 68Ga PMSA-11 PET -CT or -MRI performed within 90 days of registration and before initiation of anti-androgen or androgen deprivation therapy and demonstrating no evidence of distant metastases by (PMSA avid or non-avid nodes \<=1.5cm short axis allowed). Conventional imaging (CT, bone scan, MRI) may also be used in addition to PMSA-PET, and definitive findings of distant extra-pelvic metastases on these scans are not allowed for enrollment.
• * Staging 68Ga PSMA-11 PET -CT or -MRI demonstrating a PSMA-avid primary intra-prostatic target lesion amenable at investigator discretion to dose boost
• * All men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, for the duration of standard of care SabR and for a period of time of 6 months thereafter as per standard guidelines. Should a man's partner become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.
• * Ability to understand and the willingness to sign a written informed consent.
• * Prior curative intent local therapy (e.g. prostatectomy, radiotherapy, focal ablative therapy) for prostate cancer is not allowed, with following exceptions regarding androgen deprivation therapy (ADT)/anti-androgen therapy (AAT):
• * Subjects may not be receiving any other investigational agents for the treatment of the cancer under study.
• * History of allergic reactions to PMSA-11 68Ga imaging agent.
• * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that, in the opinion of the investigator, would limit compliance with study requirements.
• * Prior pelvic radiotherapy other than cutaneous/superficial treatments.