Inclusion Criteria:  HER2+ MBC patients scored +3 by immunohistochemical (IHC) analysis or scored +2 and the result of fluorescence in situ hybridization was positive. Patients were previously treated with trastuzumab in the advanced setting and a taxane in any setting. Patients received lapatinib (750-1,250 mg/day) plus capecitabine (1,500-2,000 mg/m2) or pyrotinib (320-400 mg/day) plus vinorelbine (25mg/ m2 intravenously or 60 mg/m2 orally on days 1 and 8 per 21 days) for at least one cycle, starting from Jun 2015 to Jan 2021. Patients had complete medical records. All data were retrospectively collected from medical records of individual institutions.  Exclusion Criteria:  Incomplete medical history