To Investigate the Real-world Efficacy and Safety of Sacituzumab Govitecan for HER2 Negative Metastatic Breast Cancer Patients in China.

Inclusion Criteria: Local recurrent or metastatic breast cancer suitable for chemotherapy, confirmed histologically. HER2-negative breast cancer(according to 2018 ASCO/CAP HER2 test guideline). 18-75 years old. ECOG PS 0～2. life expectancy is not less than 12 weeks. at least one measurable lesion according to RECIST 1.1. received at least two cycles of SG. Signed informed Exclusion Criteria: Patients who did not receive sacituzumab govitecan treatment for two or more cycles Other malignant tumors, excluding cured cervical carcinoma in situ, skin basal cell carcinoma or skin squamous cell carcinoma, have been diagnosed in the past five years. Female patients during pregnancy and lactation, fertile women with positive baseline pregnancy tests or women of childbearing age who are unwilling to take effective contraceptive measures throughout the trial History of neurological or psychiatric disorders Researchers believe that patients are not suitable for any other situation in this study.