The optimal treatment for oligometastatic prostate cancer (OMPC) is still on its way. Accumulating evidence has proven the safety and feasibility of radical prostatectomy and local or metastasis-directed radiotherapy for oligometastatic patients. The aim of this trial is to compare the safety and feasibility outcomes of metastasis-directed neoadjuvant radiotherapy (naRT) and neoadjuvant androgen deprivation therapy (naADT) followed by robotic-assisted radical prostatectomy (RARP) to ADT combined with abiraterone for treating OMPC.

The present study will be conducted as a prospective, open-label, two arms clinical trial. Patients with ≤ 3 de novo oligometastatic PCa, diagnosed on Ga-68 prostate-specific membrane antigen (PSMA) PET/CT, will be randomized in a 1:1 ratio between arm A (hormone) and arm B (neoadjuvant hormone and RT). The patients in arm A with oligometastatic PCa will receive long-term ADT combined with abiraterone. The patients in arm B with oligometastatic PCa will receive 1 month of naADT, followed by metastasis-directed radiation and abdominal or pelvic radiotherapy. Then, radical prostatectomy will be performed at intervals of 5-15 weeks after radiotherapy, and long-term ADT will be continued. The primary endpoints of the study are progression-free survival (PFS) including biochemical recurrence-free survival (bPFS), and radiological progression-free survival (RPFS). The secondary endpoints include quality of life (QoL), time to CRPC, positive surgical margin (pSM), overall survival (OS), postoperative continence, and toxicities parameters.

Inclusion Criteria:

• Histologically confirmed adenocarcinoma of the prostate without small cell features
• Oligometastatic PCa assessed by Ga-68 prostate-specific membrane antigen (PSMA), PET/CT
• <4 bone oligometastases, lymph node metastasis below the renal artery level
• Expected survival time >5 years
• World Health Organization (WHO) performance status 0-1
• Be willing to give written informed consent.

Exclusion Criteria:

• Any previous or ongoing treatment for PCa, including radiotherapy, ADT, chemotherapy, focal treatment, etc.
• Patients who have previously undergone transurethral resection or enucleation of the prostate.
• Patients who have undergone other abdominal surgery within the last 3 months
• Patients who have visceral metastases
• Patients with a history of long-term anticoagulant use and anti-platelet drug use and who stopped anticoagulant therapy less than 1 week before registration
• Patients with other malignancies and acute or chronic infections such as human immunodeficiency virus (HIV) (+), hepatitis C virus (HCV) (+) and/or positive syphilis
• Severe or active comorbidities likely to impact the advisability of radiotherapy
• Any other serious underlying medical, psychiatric, psychological, familial, or geographical condition, which, according to the judgement of the investigator, may affect the planned staging, treatment and follow-up or patient compliance or may cause high-risk treatmentrelated complications for the patient
• Patients who have participated in other clinical trials within the last 3 months
• Patients who refuse to undergo RALP
• Patients unsuitable for participation in this clinical trial as per the judgement of the investigator.

Individual participant data including baseline characteristics,treatment information and follow-up data on toxicity, survival and disease control will be shared.

Within 5 years after the publication of the study.

Data may be shared with radiation oncologists and specialists in surgerywho are interested in examining the efficacy and toxicity of oligometastatic prostate cancer treated withneoadjuvant radiohormonal therapy or androgen deprivation therapy (ADT) combined with abiraterone. Detailed study protocol should be emailed along with the request of the data. We may carefully review the study protocol, and data will only be shared with well-designed studies.