This study aimed to evaluate the effectiveness, including progression-free survival (PFS) and overall survival (OS), as well as the safety profile of SG in real-world settings by assessing the incidence of adverse events (AEs) and determining the potential impact of administering granulocyte colony-stimulating factor (G-CSF) as primary prophylaxis on the development of neutropenia secondary to SG treatment in clinically complex patients with mTNBC and HR+/HER2− mBC. This evidence concerns the gene CSF3 and Decreased total neutrophil count.