Purpose: This meta-analysis was conducted to compare the efficacy and safety of fulvestrant with aromatase inhibitors in postmenopausal women with hormone receptor-positive (estrogen and/or progesterone receptor positive) advanced breast cancer.
Methods: Electronic databases were searched for randomized controlled trials comparing the efficacy and safety of fulvestrant with three aromatase inhibitors (anastrozole/letrozole/exemestane) published through August 31, 2017. Time to progression/progression-free survival was the primary outcome, while overall survival and safety were the secondary outcomes. Time to progression/progression-free survival was evaluated in subgroups determined on age, hormone receptor status, visceral metastasis, and measurable disease. Hazard ratios with 95% confidence intervals were analyzed by STATA 12.0.
Results: Total of seven randomized controlled trials, with 3168 patients were included for analysis. In the overall population, fulvestrant and aromatase inhibitors had similar time to progression/progression-free survival (Hazard ratio 0.93; 95% confidence interval 0.86-1.01, P = 0.102); however, time to progression/progression-free survival for fulvestrant 500 mg was significantly longer compared with aromatase inhibitors (hazard ratio 0.75; 95% confidence interval 0.62-0.91, P = 0.003). Subgroup analysis revealed significant prolongation of time to progression/progression-free survival with fulvestrant compared with aromatase inhibitors in the patients of estrogen and progesterone receptor-positive (hazard ratio 0.86; 95% confidence interval, 0.75-0.98, P = 0.022) and patients aged ≥ 65 years (hazard ratio 0.81; 95% confidence interval 0.68-0.96, P = 0.014). Overall survival was similar in both groups (hazard ratio 0.89; 95% confidence interval 0.70, 1.13, P = 0.334).
Conclusion: In postmenopausal women with estrogen and/or progesterone receptor-positive advanced breast cancer, fulvestrant 500 mg showed better efficacy than aromatase inhibitor, which was not seen with fulvestrant 250 mg. Compared to aromatase inhibitors, fulvestrant prolonged time to progression/progression-free survival in the subgroups including estrogen and progesterone receptor-positive patients and those aged ≥ 65 years.
Keywords: Advanced breast cancer; Aromatase inhibitors; Fulvestrant; Hormone receptor; Postmenopausal.