Locoregional Surgery of the Primary Tumor in de Novo Stage IV Breast Cancer Patients

Inclusion Criteria: * Operable stage IV breast cancer patients,whose primary lesion is invasive breast cancer confirmed by pathology, and metastases can be confirmed by pathology or imageology examination. * ECOG-PS 0-2. * Bone marrow, liver and kidney should be fully functional. * Patients received the locoregional surgery of the primary tumor in de novo in our center, or didn't received the locoregional surgery of the primary tumor in de novo. * For the patient who accepted systematic treatment before operation, the systematic treatment must be administered within a year since diagnosed. Exclusion Criteria: * Accompanied with other primary malignant tumors. * Patients who can't plan for follow-up effectively and regularly. * Multiple liver metastasis and ALT/AST four times higher than normal at patients' first diagnosis.