HER2+ Early Breast Cancer: From Escalation via Targeted and Post-Neoadjuvant Treatment to De-Escalation

Background: Human epidermal growth factor receptor 2 positive (HER2+, also referred to as ERBB2+) breast cancer is a subtype, historically associated with a particularly poor prognosis. Research into biological and molecular pathomechanisms of breast cancer has resulted in the development and adoption of several therapies targeting HER2. In parallel, various escalation/de-escalation strategies have been examined to further optimize patient outcomes and care. Summary: In this review, we highlighted the landmark trials in the evolution of treatment and management of HER2+ early breast cancer (eBC). Key Messages: Continuous research over the last two decades has gradually prolonged survival in patients with early HER2+ eBC. Incorporation of post-neoadjuvant setting into clinical practice improved long-term outcomes in high-risk patients with residual disease after neoadjuvant therapy. In parallel, use of modern anti-HER2 agents may potentially allow omission of chemotherapy without compromising the survival in a significant number of selected patients. Current research focused on exploring the molecular heterogeneity of HER2+ breast cancer resulted in identification of new prognostic and predictive biomarkers which could pave the way toward the development of truly personalized therapy.