Efficacy of neoadjuvant endocrine therapy in HR-positive/HER2-negative breast cancer: A review

Abstract

IMPORTANCE. Neoadjuvant endocrine therapy (NET), despite demonstrating comparable data to neoadjuvant chemotherapy (NACT) in regard to ORR and being a less toxic alternative, is still used in clinical practice mainly for elderly patients or those who are not good candidates for chemotherapy. The COVID-19 pandemic led to increased application of NET for patients with HR-positive/HER2-negative breast cancer, that showed a growing need for data evaluating its efficacy in terms of long-term outcomes of treatment and for examining potential predictive biomarkers. OBSERVATIONS. We provide readers with a critical in-depth review on landmark trials comparing NET with NCT in HR-positive/ HER2-negative breast cancer. This also includes an overview of potential predictive biomarkers for identifying subsets of HR-positive breast cancer that could be safely spared neoadjuvant chemotherapy. CONCLUSIONS AND RELEVANCE. NET is an effective treatment modality for postmenopausal women diagnosed with HR-positive/ HER2-negative cancer that can downsize breast tumors. Due to the absence of large RCT comparing NET with NCT, little data on long-term outcomes, deep analysis of clinical practice treatment results is needed. Further research on potential predictive biomarkers and their validation is an important clinical issue.