Lu-PSMA for Oligometastatic Prostate Cancer Treated With STereotactic Ablative Radiotherapy

The aim of this study is to assess the progression free survival (PFS) of SABR alone and SABR + 177Lu-prostate-specific membrane antigen (PSMA) in patients with oligometastatic prostate cancer undergoing PSMA positron emission tomography (PET) staging.

Inclusion Criteria: 1. Male aged 18 years or older at screening 2. Patient has provided written informed consent 3. Histologically confirmed prostate adenocarcinoma w 4. Prior definitive treatment of the primary with either curative intent radiotherapy and/or surgery 5. Patient has 1-5 sites of nodal or bony metastases on 68Ga-PSMA or 18F-DCFPyL PET/CT 6. Adequate haematological function as defined by: * Absolute neutrophil count (ANC) ≥1.5 x 109/L * Platelet count \>150x 109/L * Haemoglobin ≥100 g/L * Creatinine Clearance ≥ 40mL/min (Cockcroft-Gault formula) 7. Assessed as suitable for SABR by a radiation oncologist 8. Patients must agree to use an adequate method of contraception 9. Have a performance status of 0-1 on the ECOG Performance Scale Exclusion Criteria: 1. Prior systemic therapy for metastatic prostate cancer. Prior ADT is allowed but ADT within 6 months of screening for the study is not allowed. If patients have received prior ADT, serum testosterone levels must be above the lower limit of normal 2. Any visceral (AJCCC M1c) metastases 3. Symptomatic cord compression, or clinical or imaging findings concerning for impending cord compression 4. Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the patient's participation for the full duration of the trial, or is not in the best interest of the patient to participate, in the opinion of the treating Investigator 5. Has a known additional malignancy that is progressing or required active treatment in the last 2 years Note: Basal cell carcinoma of the skin, squamous cell carcinoma of the skin, superficial bladder cancer or carcinoma in situ such as breast cancer in situ that has undergone potentially curative therapy are not excluded.