Hormone Therapy and Oral Medications in Breast Cancer

About 80% of cases of breast cancer have expression of the estrogen receptor (ER). Estrogen is the primary cause of cancer cell growth in ER-positive malignancies. The ER enters the nucleus upon binding estrogen and binds to DNA to trigger the production of estrogen target genes, ultimately resulting in the advancement of the cell cycle. The gold standard for treating ER-positive breast cancer is estrogen deprivation, which involves using hormone therapy to stop the body from producing estrogen or from allowing estrogen to bind to the receptor. Although endocrine therapy (ET) has proven effective, low-grade side effects may reduce quality of life in the long term. In this section, we summarized hormonal treatment options, mechanisms of action, and side effects.