BC	Breast cancer
CBR	Clinical benefit rate
Cdk4/6	Cyclin-dependent kinase 4/6
ECOG PS	Eastern Cooperative Oncology Group Performance Status
ER	Estrogen receptor
Her2	Human epidermal growth factor receptor 2
HR	Hazard ratio
MBC	Metastatic breast cancer
ORR	Objective response rate
OS	Overall Survival
PD-L1	Programmed cell death 1 ligand 1
PFS	Progression-free survival
PLD	Pegylated liposomal doxorubicin
PPE	Palmar–plantar erythrodysesthesia
PR	Progesterone receptor
SD	Stable disease
SERD	Selective estrogen receptor degrader
TNBC	Triple-negative breast cancer
TTNC	Time to next chemotherapy