Rezvilutamide in Patients With Biochemical Recurrence After Radical Prostatectomy for Prostate Cancer

Main Inclusion Criteria: 1. Age ≥ 40 years, male. 2. Patients with histologically-confirmed diagnosis of prostate adenocarcinoma. 3. pathologically node-negative (pN0) or pathologically node cannot be assessed (pNx); 4. Patients with PSA \< 0.1ng/ml within 8 weeks after radical prostatectomy (RP) and maintained for at least 6 months; 5. Biochemical recurrence (two consecutive rises in PSA with absolute values \> 0.2ng/ml, the time interval ≥ 2 weeks apart ) and no local recurrence or distant metastatic lesions on conventional imaging (bone scan and CT/MRI scan); 6. Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 1; 7. Estimated life expectancy \>10 year; 8. Adequate laboratory parameters * Absolute Neutrophil Count (ANC) ≥ 1.5 x 10\^9/L * Platelet count (PLT) ≥ 100 x 10\^9/L * Haemoglobin (Hb) ≥ 90 g/L * Serum creatinine (Cr) ≤ 1.5 x upper limit of normal(ULN) or creatinine clearance \> 50 ml/min. * Total bilirubin (TBIL) ≤ 1.5 x ULN. * Glutamic oxaloacetic transaminase (AST/SGOT) or glutamic alanine transaminase (ALT/SGPT) levels ≤ 2.5 x ULN. * International normalised ratio (INR) ≤1.5, prothrombin time (PT) and activated partial thromboplastin time (APTT)≤1.5 x ULN . * Left ventricular ejection fraction (LVEF) ≥ 50%. 9. Patients able to comply with the protocol. Arm 1 subjects are proposed to receive salvage radiation therapy, while arm 2 subjects are not suitable for or refuse radiation therapy. 10. Signed informed consent. Main Exclusion Criteria: 1. Prior hormonal therapy (antiandrogens or gonadotropin releasing hormone) or prior radiotherapy to pelvic . 2. Postoperative biochemical recurrence with PSA \> 2 ng/ml. 3. Postoperative pathology containing neuro-endocrine differentiation or small cell features. 4. Prior malignancy other than prostate cancer in the past three years. 5. History of any of the following: * Seizure or known condition that may pre-dispose to seizure * Severe or unstable angina, myocardial infarction, symptomatic congestive heart failure, arterial or venous thromboembolic events (eg, pulmonary embolism, cerebrovascular accident including transient ischemic attacks), or clinically significant ventricular arrhythmias within 6 months prior to entry. * Active infection (eg, human immunodeficiency virus \[HIV\] or viral hepatitis) 6. Any other serious or uncontrolled illness which in the opinion of the investigator makes it undesirable for the patient to enter the trial.