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.