The aim of this trial is to explore the real-world effectiveness and poteintial predictors of Sacituzumab Govitecan in Chinese metastatic breast cancer patients.

Inclusion Criteria:

1. Patients aged over 18 years old.
2. Metastatic breast cancer included unresectable locally advanced breast cancer, de novo stage IV breast cancer, and recurrent metastatic breast cancer.
3. Plan to receive or has received Sacituzumab Govitecan monotherapy
4. Available medical history.

Exclusion Criteria:

1. Incomplete medical history.
2. Pregnancy or breast-breeding

Patients aged over 18 years old with metastatic breast cancer included unresectable locally advanced breast cancer, de novo stage IV breast cancer, and recurrent metastatic breast cancer.