1254 - Adjuvant Docetaxel Following Radiotherapy Plus Long-Term ADT for Grade Group 5 Non-Metastatic Prostate Cancer: A Prospective, Comparative Cohort Study

10:55am - 11:00am ET

Room 107

Presenter(s)

Mingwei Ma, MD - Peking University First Hospital, Beijing, Beijing

M. Ma¹, H. Chen¹, X. S. Gao¹, H. Li¹, M. Sun², X. Y. Ren¹, J. Chen¹, and W. Yu³; ¹Department of Radiation Oncology, Peking University First Hospital, Beijing, China, ²Department of Chemotherapy, Peking University First Hospital, Beijing, China, ³Department of Urology, Peking Universtiy First Hospital, Beijing, China

Purpose/Objective(s): Guidelines support systemic intensification in very high-risk disease; evidence for systemic intensification in M0 high-risk disease remains evolving. Grade Group 5 (GG5) prostate cancer is associated with aggressive tumor biology and may exhibit limited sensitivity to endocrine manipulation, highlighting the rationale for treatment intensification beyond standard anti-androgen–based regimens. This study was designed to evaluate the efficacy and safety of adding adjuvant docetaxel to standard radical treatment in patients with GG5 non-metastatic prostate cancer.

Materials/Methods:

A prospective cohort study was conducted to consecutively enroll patients diagnosed with non-metastatic prostate adenocarcinoma (GG5) between 2019 and 2025. Following standard radical treatment, which included radical radiotherapy or postoperative radiotherapy, patients were assigned to the standard therapy group or the adjuvant Doc group. Patients in the adjuvant Doc group received 4-6 cycles of Doc after completing standard treatment. The primary observational endpoint was Failure-Free Survival (FFS). Secondary endpoints included Biochemical Relapse-Free Survival (BRFS), Metastasis-Free Survival (MFS), Overall Survival (OS), and Adverse Events. Statistical analyses were performed using a log-rank test and multifactorial Cox regression analysis.

Results:

492 patients were enrolled in the study, with 392 in the standard therapy group and 100 in the adjuvant Doc group. All patients received standard radical treatment. The median age was 68.5 years (range, 48-87), and the median follow-up period was 33.5 months (interquartile range, 19.3-49.8). The 6-year outcomes demonstrated significant differences between the two groups. The adjuvant Doc group showed superior FFS (86.2% vs. 66.5%, p=0.002) and BRFS (87.1% vs. 72.7%, p=0.002), compared to the standard therapy group. A 1:2 matching procedure was performed based on 6 baselines, including age, PSA, and others, resulting in 258 matched patients (with 168 in the standard therapy group and 90 in the adjuvant Doc group). Survival analysis post-matching further confirmed the superiority of the adjuvant Doc group over the standard therapy group, with 6-year FFS (85.9% vs. 66.0%, p=0.005) and BRFS (86.9% vs. 72.0%, p=0.006) being significantly better. Regarding adverse events, the overall tolerability was acceptable. However, the incidence of grade 3 and above leukopenia or neutropenia was significantly higher in the adjuvant Doc group compared to the standard therapy group (p < 0.05).

Conclusion: In this prospective cohort of GG5 non-metastatic prostate cancer, adjuvant docetaxel was associated with improved early disease-control endpoints (FFS/BRFS) and increased hematologic toxicity, while no significant differences in MFS or OS were observed with the current follow-up; longer follow-up is warranted to assess long-term survival benefit.