This study aims to evaluate the efficacy of adjuvant docetaxel chemotherapy following radical radiotherapy in patients with localized high-grade prostate cancer. Eligible participants include those diagnosed with prostate cancer confirmed by biopsy or surgical pathology, with a Gleason score of 9-10 or containing a Gleason 5 component, and no evidence of distant metastasis. Patients will be divided into two groups: the standard treatment group receiving only radical treatment (radiotherapy or surgery), and the standard treatment plus chemotherapy group, receiving four to six cycles of docetaxel chemotherapy after standard treatment. The primary endpoint is Failure-Free Survival (FFS), with secondary endpoints including Biochemical Relapse-Free Survival (BRFS), Metastasis-Free Survival (MFS), Overall Survival (OS), and assessment of adverse events The study aims to better understand the impact of adjuvant chemotherapy on the prognosis of patients with high-risk prostate cancer and determine whether it improves survival outcomes.

Inclusion Criteria:

1. Histologically confirmed prostate cancer diagnosed by biopsy or surgery with a Gleason score of 9-10 (GG grade 5) or containing Gleason 5 components.
2. No evidence of distant metastasis confirmed by imaging.
3. Expected to receive standard radical treatment or postoperative radiotherapy.
4. Estimated survival time greater than 12 months.
5. Aged ≥ 18 years.
6. Karnofsky Performance Status (KPS) ≥ 80.
7. Adequate blood count: white blood cell ≥ 3.5 × 10^9/L, neutrophils ≥ 1.5 × 10^9/L, platelets ≥ 100.0 × 10^

Exclusion Criteria:

1. History of malignant tumors (except those cured for more than 5 years).
2. Previous abdominal radiation therapy.
3. Weight loss > 10% within the past 6 months.
4. Pre-existing or concomitant bleeding disorders.
5. Active infections.
6. Significant cardiovascular disease (e.g., controlled hypertension, unstable angina, NYHA class ≥ II congestive heart failure, unstable symptomatic arrhythmias, or ≥ II peripheral vascular disease) or any condition deemed intolerable to chemotherapy by the oncology department.