Bicalutamide Plus Aromatase Inhibitors in ER(+)/AR(+)/HER2(-) Metastatic Breast Cancer

Inclusion Criteria: * Patients with histologically confirmed estrogen receptor positive, androgen positive and HER2 negative breast cancer * Metastatic or unresectable locally advanced disease * Age over 18 years * Postmenopausal status （continuous using luteinizing hormone releasing hormone(LHRH) analogue is available） * Patient must have disease progression after treatment of an Aromatase inhibitor. * Eastern Cooperative Oncology Group (ECOG) performance status (PS)0-2 * Life expectancy over 3 months. * Measurable disease according to RECIST version 1.1 or only bone metastasis * Adequate hematological, hepatic function. * Voluntarily signed and dated written informed consent prior to any study specific procedure. Exclusion Criteria: * Patient with life-threatening visceral metastasis, such as extensive liver metastasis, brain or meningeal metastasis * Concomitant diseases/conditions that is not controllable, and Any other major illness that, in the Investigator's judgment, will substantially increase the risk associated with the patient's participation in this study. * History of other primary malignancy * Resistant to steroidal or nonsteroidal aromatase Inhibitor