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.

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.

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).

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.