However, different from western countries, the majority (50-55%) of patients are premenopausal women in Asia including China.The benefit of everolimus plus endocrine therapy in premenopausal women have not yet been well delineated. Although there was a report that efficacy was comparable between premenopausal metastatic breast cancer patients treated with letrozole plus goserelin and postmenopausal patients treated with letrozole alone as first line hormone therapy, it is generally accepted that endocrine treatment outcome in premenopausal women, especially in younger age is known to be poor. So the addition of everolimusin this population would be a potential viable treatment option to overcome resistance to endocrine therapies that needs to be evaluated.