Maximal Cytoreductive Therapies on Post-treatment Metastases in Pts With mHSPC During Apalutamide Plus ADT Treatment (CHAMPION)

Inclusion Criteria: Able to understand and willing to sign the informed consent; Aged ≥18 years; Histologically or cytologically confirmed prostate adenocarcinoma (primary small cell carcinoma or signet-ring cell carcinoma of the prostate are not allowed, however adenocarcinoma with neuroendocrine differentiation accounting ≤10% is allowed); Newly diagnosed prostate cancer (within 3 months prior to enrollment); M1a/b disease with the presence of 1-10 visible metastases at diagnosis by conventional imagine including bone scan (ECT) and CT or MRI of the chest, abdomen, and pelvis; With initial systemic treatment of apalutamide plus ADT and willing and expected to comply with treatment and follow up schedule [No more than 2-month systemic treatment before enrollment (including ADT and ADT combined with short-term first-generation anti-androgen therapy (flutamide or bicalutamide); To maximize enrollment, patients who had started apalutamide plus ADT before enrollment are allowed into the study provided that they are otherwise eligible and therapy was initiated no longer than 2 months before enrollment]; Fit to undergo cytoreductive radical prostatectomy and radiotherapy to the visible sites of metastases; ECOG PS score is 0-1; Adequate organ function; Life expectancy ≥ 12 months. Exclusion Criteria: History of allergies, hypersensitivity, or intolerance to any drug used in the study; Had the contraindications or is intolerant to cRP or RT; Had any visceral metastases (brain, liver, lung etc.) on screening conventional imaging (bone scans, CT or MRI); Prior Received any of the following treatments for primary and metastatic prostate cancer; >2-month ADT or first-generation antiandrogens (bicalutamide, flutamide etc.); Any other novel hormonal therapies (enzalutamide, darolutamide, abiraterone etc.) except ≤ 2-month apalutamide plus ADT listed in inclusion criteria; Any chemotherapy; local treatment or metastatic treatment for primary prostate cancer or metastases; Any immunotherapy (PD-L1 etc.), target therapy (PARPi etc), etc; History of seizure or known condition that may predispose to seizure; History of major surgery 4 weeks before enrollment; Had major cardiovascular and cerebrovascular diseases within 6 months prior to the start of the study; Any condition that could interfere with drug absorption(e.g. unable to swallow, chronic diarrhea etc. ); Conditions of active infection; History of previous or current malignant disease, except for curatively treated tumors cured for more than 3 years; Patients who is currently undergoing other trials; Unwilling or difficult to cooperate with treatment and follow-up visit; Other sever conditions which could interfere with trial safety or results judged by the investigator.