Pyrotinib Combined With Capecitabine in HER-2 Positive Advanced Breast Cancer and Brain Metastases (Post-PERMEATE)

Inclusion Criteria: 1. Pathologically diagnosed patients with HER-2 expression-positive advanced breast cancer; Note: Positive HER2 expression refers to at least one tumor cell immunohistochemical staining intensity of 3+ or fluorescence in situ hybridization \[FISH\] in the pathological detection/recheck of the primary or metastatic lesions performed by the pathology department of the participating central hospital confirmed positive; 2. Brain metastases are diagnosed by MRI/enhanced CT imaging, according to RECIST 1.1 criteria, with or without measurable lesions and with or without symptoms of brain metastases; 3. Pyrotinib combined with capecitabine in the treatment of brain metastases with non-PD evaluation at the first treatment, at least ≥ 2 continuous imaging reports or assessments 4. For previous treatment regimens, no previous use of capecitabine or progression after capecitabine discontinuation for 6 months, or progression after discontinuation of capecitabine adjuvant therapy for one year or more; 5. There are traceable medical history data. Exclusion Criteria: 1. Patients enrolled in the previous PERMEATE study; 2. The research program is receiving other anti-tumor drug treatment at the same time; 3. The initial dose of pyrotinib is lower than the minimum dose in the instructions (240 mg), and the capecitabine is 50% lower than the standard dose; 4. Pyrotinib combined with capecitabine in the treatment of non-brain metastases and progressive patients; 5. The investigator believes that the patient is not suitable to enter this study.