Is There a Benefit of Addition Docetaxel, Abiraterone, Celecoxib, or Zoledronic Acid in Initial Treatments for Patients Older Than 70 Years With Hormone-sensitive Advanced Prostate Cancer? A Meta-analysis

Abstract

Background: Results from large randomized controlled trials combining docetaxel, abiraterone, celecoxib, or bisphosphonates with androgen deprivation therapy (ADT) in hormone-sensitive prostate cancer have emerged. However, in our knowledge, few data are available in patients older than 70 years. Therefore, we undertook a meta-analysis of all published phase III studies.

Materials and methods: We performed a PubMed search using the keywords: "hormone sensitive prostate cancer," "phase III studies," "docetaxel," "abiraterone," "celecoxib," and "bisphosphonates." We also screened American Society of Clinical Oncology and European Society for Medical Oncology proceedings. Combination therapies were compared with ADT alone. The efficacy outcomes were overall survival (OS) and progression-free survival (PFS). Hazard ratios (HRs) with their 95% confidence intervals (CIs) were collected from the studies and pooled. A hazard ratio of less than 1.00 favored the combination group.

Results: This meta-analysis included 8 studies: 3 assessed docetaxel (CHAARTED, STAMPEDE arm E and C), 2 others assessed abiraterone (LATITUDE and STAMPEDE arm G); 2 others assessed celecoxib (STAMPEDE arm D and F), and the last one assessed zoledronic acid alone (STAMPEDE arm B). Our meta-analysis included 2264 patients (86% with metastases). Concerning age, we chose a cutoff of 70 years, corresponding to the available data for each study. The performance index was 0 to 1 for about 90% of patients. Overall, in patients > 70 years old, the addition of docetaxel statistically improved PFS (HR, 0.51; 95% CI, 0.42-0.61) but not OS (HR, 0.86; 95% CI, 0.69-1.07). The addition of abiraterone to ADT also statistically improved PFS (HR, 0.49; 95% CI, 0.37-0.64) but not OS (HR, 0.85; 95% CI, 0.67-1.08), as well as the addition of celecoxib (HR, 0.67; 95% CI, 0.53-0.85 and HR, 0.95; 95% CI, 0.73-1.25, respectively). The addition of zoledronic acid did not improve PFS or OS (HR, 0.78; 95% CI, 0.61-1.00 and HR, 0.99; 95% CI, 0.71-1.38, respectively).

Conclusions: The addition of docetaxel, abiraterone, or celecoxib to ADT significantly increased PFS in older men with hormone-sensitive advanced prostate cancer. However, the benefit in OS is not statistically significant. Further studies are needed to define the best first-line strategy in this subgroup.

Keywords: Abiraterone; Docetaxel; Elderly; First-line; Metastatic prostate cancer.