This study is a single-arm clinical trial, and eligible patients will be enrolled. For the enrolled patients, they will receive an intravenous infusion of homoharringtonine (1 mg) plus an intravenous infusion of 5% glucose injection (250 ml), once daily for two consecutive days. Patients with localized high-risk/very high-risk and regional lymph node-metastatic prostate cancer will receive at least one cycle of the above treatment plus continuous androgen deprivation therapy; patients with metastatic prostate cancer will receive one cycle of treatment, followed by a three-week interval before repeated medication, with the treatment repeated for a total of at least three cycles plus continuous androgen deprivation therapy. All patients will undergo radical prostatectomy within 3 weeks (±7 days) after the end of treatment.