Adjuvant therapy for hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative early breast cancer is shifting from experience-based practice to precision risk stratification. Multigene assays increasingly guide chemotherapy de-escalation, endocrine intensification and extension, and decisions on adjuvant radiotherapy. In high-risk populations, cyclin-dependent kinases 4/6 inhibitors (abemaciclib, ribociclib, dalpiciclib) have established an evidence base for adjuvant use. Key evidence from long-term ovarian function suppression follow-up in premenopausal women and extended therapy in postmenopausal women provides a crucial basis for tailored treatment duration. Neoadjuvant immunotherapy can improve the pathological complete response rate in a subset of biologically enriched HR-positive early breast cancer. The advancement of antibody-drug conjugates into earlier lines of therapy for the HER2-low expression population shows promising potential, possibly replacing some conventional chemotherapy.
