A Phase II Trial of PSMA-Directed Para-Aortic Radiation Therapy for Oligorecurrent Prostate Cancer - The OCEAN Trial

Inclusion Criteria: 1. Histologically proven prostate adenocarcinoma 2. Male, ≥ 18 years old 3. Oligorecurrent disease limited to the sub-diaphragmatic region with or without pelvic lymph nodes * a. No more than a total of 5 lesions on PSMA PET/CT scan (each lesion defined as positive with standardized uptake value (SUV) \> liver uptake and CT scan correlate) * b. No disease outside of the pelvic and sub-diaphragmatic para-aortic lymph nodes * c. At least one lesion in the sub-diaphragmatic pelvic or para-aortic lymph nodes * d. Non-bulky nodal disease (ie, tumor \<5 cm) 4. Prior pelvic radiation with disease response * a. Definitive radiation therapy to the prostate with or without treatment of the pelvic lymph nodes and/or * b. Salvage or adjuvant radiation therapy to the prostate bed following prostatectomy with or without treatment of the pelvic lymph nodes 5. Hormone-sensitive prostate cancer 6. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-2 7. Ability to understand the investigational nature, potential risks and benefits of the research study, and willingness to sign the written informed consent and HIPAA document(s) 8. Willingness to fill out quality of life and psychosocial forms 9. Willingness to participate in our institution's Prostate Cancer Database Protocol (ID# 20090767) Exclusion Criteria: 1. No pathological diagnosis of prostate adenocarcinoma 2. Patient has more than 5 sites of metastatic disease 3. Patient has history of bone and/or visceral metastasis 4. No evidence of disease in the para-aortic or pelvic lymph nodes 5. No staging with PSMA PET/CT scan 6. History of prior radiation therapy outside the pelvis for prostate cancer 7. Bulky nodal disease \>5 cm in tumor size 8. Androgen deprivation therapy (ADT) or chemotherapy in the three months prior to staging PSMA PET/CT scan (suggesting oligoprogressive disease, rather than true oligorecurrent disease) or at time of study enrollment 9. Suspicious radiologic evidence of disease in the prostate on staging PSMA PET/CT scan without confirmatory negative prostate biopsy 10. Implanted hardware which limits treatment planning or delivery (determined by treating physician) 11. Castration-resistant prostate cancer (history of rising PSA with serum testosterone level \<50 ng/dL) 12. Patients with ECOG performance status \> 2 13. History of inflammatory bowel disease 14. History of malignancy other than prostate cancer except for non-melanoma skin cancer 15. Patients unable to consent or are prisoners 16. Unwilling to fill out quality of life and psychosocial forms 17. Participants with impaired decision-making capacity