Management of Hormone Receptor-Positive Metastatic Breast Cancer

Abstract

Hormone-receptor positive HER2-negative breast cancer constitutes about 2/3 of breast cancer. Hormonal therapy such as tamoxifen and aromatase inhibitors has been the main stay of treatment which gives favorable quality of life compared with traditional chemotherapy. However, the efficacy of subsequent hormonal therapy declines rapidly after the patients develops resistance to first line hormonal therapy. In recent years, there have been many breakthrough in the treatment of this cancer. A number of targeted agents including CDK4/6 inhibitor and mTOR inhibitor are now part of standard treatment paradigm to help prolong the use of hormonal therapy. New understanding in potential biomarker of resistance such as ESR1 mutation or PIK3CA mutation has also empowered us to develops personalized approach in treatment. This article will explain the treatment logistic for this cancer, current knowledge in hormonal resistance, findings of key clinical trials that define the current treatment paradigm, efficacy and major side effect precaution of the targeted agents, and the unmet needs.