CONVERT-HB1: Radical Prostatectomy After Systemic Therapy for High-volume Metastatic Hormone-sensitive Prostate Cancer

Inclusion Criteria:

1. Male patients aged \>18 and ≤70 years, or with an estimated life expectancy \>10 years.
2. Histologically or cytologically confirmed prostate adenocarcinoma with neuroendocrine differentiation ≤10%, and no small cell or signet-ring cell carcinoma component.
3. High-volume metastatic disease according to CHAARTED definition: presence of visceral metastasis and/or ≥4 bone lesions with at least one lesion outside the axial skeleton (vertebral bodies and pelvis).
4. Newly diagnosed metastatic hormone-sensitive prostate cancer (mHSPC) who started intensified endocrine therapy within 3 months.
5. ECOG performance status 0-2.
6. Adequate bone marrow, liver, renal, and coagulation function as defined in the protocol (ANC ≥1.5×10\^9/L, hemoglobin ≥9.0 g/dL, platelets ≥80×10\^9/L; TBIL ≤1.5×ULN; AST/ALT/ALP ≤2.5×ULN; albumin ≥30 g/L; creatinine ≤2×ULN or creatinine clearance ≥30 mL/min; INR ≤1.5 in patients not receiving anticoagulation).
7. Patients voluntarily sign informed consent and are willing and able to comply with study procedures.

Exclusion Criteria:

1. History of hypersensitivity or intolerance to any study drugs.
2. mCRPC (metastatic castration-resistant prostate cancer).
3. Oligometastatic mHSPC intended for upfront radical prostatectomy.
4. History of seizure, medications that may lower seizure threshold, or conditions predisposing to seizures (e.g., TIA, stroke, significant head trauma with loss of consciousness requiring hospitalization) within 12 months before starting study treatment.
5. Major surgery within 4 weeks prior to starting study treatment.
6. Significant cardiovascular or cerebrovascular disease within 6 months (e.g., unstable angina, myocardial infarction, NYHA class III or higher heart failure, stroke, clinically significant arrhythmia requiring treatment).
7. Conditions affecting drug intake or absorption (e.g., inability to swallow, chronic diarrhea, intestinal obstruction).
8. Active infection (e.g., HIV positive, HBsAg positive, HCV positive) which in the investigator's opinion may affect safety or efficacy assessment.
9. Other malignancies within the past 3 years, except adequately treated basal cell carcinoma of the skin.
10. Known brain metastases or leptomeningeal disease.
11. Concurrent participation in another interventional clinical trial or receiving other investigational drugs/devices.
12. Poor compliance or inability to adhere to study procedures and follow-up.
13. Any other severe uncontrolled comorbidities (e.g., poorly controlled hypertension, severe diabetes, neurologic or psychiatric disorders) or conditions that may interfere with study conduct or interpretation, as judged by the investigator.