The goal of this clinical trial is to evaluate efficacy and safety of radical prostatectomy (RP) with or without salvage radiotherapy versus RP with extended pelvic lymph node dissection (ePLND) in males who have localized intermediate/high-risk prostate cancer with a Briganti nomogram no less than 7%. The main questions this study aim to answer are:

1. Is RP with or without salvage radiotherapy non-inferior to RP with ePLND in efficacy for patients with localized intermediate/high-risk prostate cancer with a Briganti nomogram no less than 7%?
2. Will complication rates of RP with or without salvage radiotherapy be significantly lower than those of RP with ePLND?

Researchers will compare the experimental arm (robot-assisted laparoscopic radical prostatectomy with or without salvage radiotherapy) versus the control arm (robot-assisted laparoscopic radical prostatectomy with ePLND) to see if differences exist in oncological efficacy and safety outcomes.

Participants will:

1. Undergo one of the following surgical interventions:

   1. Robot-assisted laparoscopic radical prostatectomy (RARP) with extended pelvic lymph node dissection (ePLND), OR
   2. RARP alone, followed by salvage radiotherapy only if biochemical recurrence occurs postoperatively

2. Complete scheduled monitoring activities:

   1. Serum PSA testing: Monthly or every 3 months within 2 years after surgery
   2. PSMA PET/CT scans: Annually until study completion
   3. Report all treatment-related complications within 24 hours of onset

Inclusion Criteria:

• Provided signed and dated informed consent form.

• Be male aged 18-80 years at consent.

• Commit to protocol compliance and complete all study procedures.

• Medically fit to tolerate interventions, including PSMA PET imaging, RARP, pelvic radiotherapy.

• Diagnosis of localized intermediate/high-risk prostate cancer (miN0M0):

  i. Confirmed by: systematic biopsy + PSA + PSMA PET/MRI. ii. Briganti nomogram (2017)≥7%. iii. Candidate for radical prostatectomy. iv. D'Amico:

  1. Intermediate-risk: PSA 10-20ng/mL OR Gleason 7 (ISUP Grade 2/3) OR cT2b;

  2. High-risk: PSA>20ng/mL OR Gleason>7 (ISUP Grade 4/5) OR cT2c.

     Exclusion Criteria:

• Prior treatments for prostate cancer, including radiotherapy, chemotherapy or endocrine therapy.

• Non-acinar adenocarcinoma histology on biopsy.

• Preoperative evidence of metastasis: nodal(N1), locally advanced(T3-4), or distant(M1) disease on imaging.

• History of pelvic lymphadenectomy or radiotherapy.

• Other malignancies within 5 years.

• Contraindications to radical prostatectomy or being deemed surgically inoperable upon clinical assessment.

• Contraindications to radiotherapy or intolerance determined by radiation oncologists.

• Severe allergy to PSMA PET ligands or excipients.

• Any other conditions precluding PSMA PET examination.