Abstract: At present,the incidence of breast cancer has been the first in the world,and hormone receptor-positive (HR⁺) / human epidermal growth factor receptor 2-negative (HER2^-) advanced breast cancer has seriously affected the prognosis of patients.In the past,the therapeutic drugs were mainly third-generation aromatase inhibitors (AI) and fulvestrant.In recent years,the era of endocrine therapy combined with cyclin-dependent kinase4/6(CDK4/6) inhibitors has begun.Different CDK4/6 inhibitors have different related adverse events,and they need to evaluate the physical condition of patients and develop a treatment plan,but neutropenia is prevalent.Everolimus,Alpelisib,and Chidamide are second-line therapeutic drugs.

Key words: hormone receptor positive, advanced breast cancer, CDK4/6 inhibitor