Deutenzalutamide and Hormone Therapy Before and After Surgery With Docetaxel Before Surgery for High-Risk Localized or Locally Advanced Prostate Cancer

This study will assess the effects and safety of deutenzalutamide combined with hormone therapy before and after prostate cancer surgery, with docetaxel chemotherapy added before surgery. It is intended for men with high-risk localized or locally advanced prostate cancer who have no distant spread on imaging and are suitable for surgery. The researchers will measure how often treatment leaves no cancer or only a very small amount of cancer in the prostate, with no cancer in the pelvic lymph nodes removed during surgery. They will also assess whether participants can undergo the planned surgery, what side effects occur, and whether the cancer returns or spreads during follow-up. Up to 37 participants will be enrolled at several hospitals. All participants will be assigned to the same treatment plan; there is no comparison group. The planned treatment includes: * Deutenzalutamide taken by mouth each day, together with hormone therapy to lower testosterone levels, for 24 weeks before surgery. * Docetaxel given through a vein once every 3 weeks for six cycles during the treatment period before surgery. * Surgery to remove the prostate and pelvic lymph nodes, when medically appropriate. * A further 24 weeks of deutenzalutamide and hormone therapy after recovery from surgery, without further docetaxel. Hormone therapy will continue across the treatment periods for a total of at least 13 months. Treatment may be adjusted or stopped according to side effects and the participant's condition. Follow-up is planned for up to 5 years after all study treatment has ended. Participants may also choose to join an optional study using a single blood sample collected before treatment and leftover tissue from their diagnostic prostate biopsy. These samples will be used to explore features that may be associated with treatment response and later outcomes. Participation in this optional component is not required to receive the study treatment.

Inclusion Criteria: * Inclusion Criteria: * Men aged 18-80 years with histologically confirmed high-risk localized or locally advanced prostate adenocarcinoma. * High-risk disease is defined by meeting either (1) or (2): 1. NCCN high-risk criteria: at least one of the following:Gleason score \>=8;Prostate-specific antigen (PSA) \>=20 ng/mL;Clinical T stage \>=T3. 2. Study-specific biopsy criteria: overall Gleason score \>=4+3 (International Society of Urological Pathology \[ISUP\] Grade Group \[GG\] 3-5), plus at least one of the following:(a) \>=6 systematic biopsy cores showing Gleason 4+3 (GG3) or Gleason 8 (4+4 or 5+3), including at least one Gleason-8 core. Only systematic cores are counted; targeted cores are excluded from this count;(b) \>=3 systematic biopsy cores showing Gleason 4+3 (GG3) or Gleason 8 (4+4 or 5+3), PSA \>=20 ng/mL, and at least one Gleason-8 core. Only systematic cores are counted; targeted cores are excluded from this count;(c) \>=1 systematic or targeted biopsy core with Gleason score \>=9 (GG5). Both systematic and targeted cores may be counted, without counting the same core more than once;(d) \>=2 distinct, evaluable systematic or targeted biopsy cores, each with Gleason score \>=8 (GG4-5) and tumor involvement \>=80%. Core counting and tumor involvement are determined according to the protocol's standardized rules. * No distant metastases (cM0) on baseline imaging; cN0 or pelvic cN1 below the common iliac artery bifurcation is permitted. Suitable for radical prostatectomy and pelvic lymph node dissection. * Eastern Cooperative Oncology Group (ECOG) performance status 0-1; life expectancy \>=10 years; able to receive androgen-deprivation therapy for \>=13 months. * Adequate organ function, assessed after \>=14 days without blood-component transfusion or hematopoietic support: neutrophils \>=1.5 x 10\^9/L; platelets \>=100 x 10\^9/L; hemoglobin \>=9 g/dL; potassium \>=3.5 mmol/L; ALT and AST \=2 peripheral sensory or motor neuropathy. * Another malignancy currently or within the previous 2 years. * Major surgery requiring general anesthesia within 28 days before the first dose. * Use of prohibited urinary-symptom or PSA-altering medications during deutenzalutamide treatment, including finasteride, dutasteride or phytoestrogens. * Seizure history or conditions increasing seizure risk, including stroke within 1 year before the first study anticancer dose or cerebral arteriovenous malformation; benign central nervous system/meningeal disease expected to require surgery or radiotherapy during study treatment. * Alcohol or drug abuse/dependence. * Participation in another therapeutic clinical trial within 1 month before study treatment. * Any other condition considered unsuitable by the investigator.