Anastrozole plus fulvestrant vs. anastrozole alone for hormone receptor-positive advanced breast cancer: a meta-analysis of randomized controlled trials.

Background: For patients with hormone receptor (HR)-positive advanced breast cancer, whether the combination of anastrozole and fulvestrant is more effective than anastrozole alone is controversial. Our meta-analysis aimed to compare the efficacy and safety of the two therapies.

Methods: We retrieved relevant studies in Embase, the Cochrane Library, Ovid MEDLINE, PubMed, ScienceDirect, Web of Science, Scopus, and Google Scholar. The primary outcomes were overall survival (OS) and progression-free survival (PFS). The secondary outcomes were the disease control rate (DCR), the objective response rate (ORR), and adverse events (AEs).

Results: Five articles based on 4 randomized controlled trials containing 2146 patients were identified in our meta-analysis. The combination group had better efficacy in the endpoints of OS (hazard ratio [HR] 0.86; 95% confidence interval [CI] 0.74-0.99, p = 0.03) and PFS (HR 0.87; 95% CI 0.77-0.97, p = 0.02). Regarding the ORR, DCR, total AEs and grade 3-5 AEs, we found no difference between the two treatments. The combination group showed a clearly higher rate of treatment discontinuations (95% CI 1.05-3.60, p = 0.03) and AEs leading to death (95% CI 1.12-9.11, p = 0.03). The subgroup analysis of AEs showed an increased incidence of extremity or muscle pain, hematologic effects, gastrointestinal disorders, and hot flashes in the combination group.

Conclusions: For HR-positive advanced breast cancer patients, the combination of anastrozole and fulvestrant appears to be superior to anastrozole alone in extending PFS and OS, despite relatively serious AEs.