Aromatase Inhibitor Versus Tamoxifen in Postmenopausal Woman With Advanced Breast Cancer: A Literature-Based Meta-Analysis

Clinical trials have reported conflicting results as to whether Aromatase inhibitors (AIs) as first-line hormonal therapy improve outcome over tamoxifen in postmenopausal women with advanced breast cancer. We performed a meta-analysis comparing primary and secondary endpoints of AIs to tamoxifen as first-line hormonal therapy in postmenopausal women with advanced breast cancer. The event-based odds ratio (OR) with 95% confidence interval (95% CI) were derived, and a test of heterogeneity was applied. Six eligible trials (2560 patients) were selected from 488 studies that initially were identified. A significant difference in favoring AIs over tamoxifen was observed in overall response rate (ORR; OR, 1.56; 95% CI, 1.17-2.07; P = .002) and clinical benefit (CB; OR, 1.70; 95% CI, 1.24-2.33; P = .0009). Whereas the trend toward an improved overall survival (OS) rate was not significant (OR, 1.95; 95% CI, 0.88-4.30; P = .10). Toxicities did not differ significantly except vaginal bleeding (OR, 0.30; 95% CI, 0.16-0.56; P = .0002) and thromboembolic event (OR, 0.47; 95% CI, 0.28-0.77; P = .003). AIs appeared to be effective and feasible compared with tamoxifen as first-line hormonal therapy in postmenopausal women with advanced breast cancer. Further prospective, randomized, controlled trials will be necessary.