Metronomic Capecitabine Plus Aromatase Inhibitor for First Line Treatment in HR(+), Her2(-) Metastatic Breast Cancer

Inclusion Criteria: * Adult women with locoregionally recurrent or metastatic disease not amenable to curative therapy * Confirmed diagnosis of ER positive/Her2-negative breast cancer * No prior systemic anti-cancer therapy for locoregionally recurrent or metastatic disease * Any menopausal status, but premenopausal or perimenopausal patients are required to receive LHRHa treatment * Measurable disease defined by RECIST version 1.1, or bone-only disease * Eastern Cooperative Oncology Group (ECOG) 0-2, and life expectancy ≥ 3 months * Adequate organ and marrow function * Resolution of all toxic effects of prior therapy or surgical procedures Exclusion Criteria: * Patients who have progressed within 2 years of adjuvant endocrine therapy * Patients who have not received prior endocrine therapy and are eligible to receive fulvestrant as initial therapy * Patients with advanced, symptomatic, visceral spread that are at risk of life threatening complication in the short term * Known uncontrolled or symptomatic central nervous system metastases * Diagnosis of any other malignancy within 3 years prior to randomization (except adequately treated basal or squamous cell skin cancer or cervical carcinoma in situ) * Serious uncontrolled intercurrent infections or intercurrent medical or psychiatric illness