Endocrine Therapy for Breast Cancer - A Success Story in All Treatment Settings

Endocrine treatment for hormone receptor positive breast cancer has a proven role in all settings, ie neo-adjuvant, adjuvant and palliative care. Tamoxifen had been the standard of care for all women with breast cancer in adjuvant setting for many years by improving the disease free survival (DFS) and overall survival (OS). Tamoxifen remains the only approved treatment in all settings for pre-and peri-menopausal women with breast cancer. Aromatase inhibitors (AIs) later became the standard of care in all treatment settings for post-menopausal women by demonstrating advantage in DFS and in some studies OS. Ovarian function suppression (OFS) was tested in many trials and proved to be effective in adjuvant and metastatic settings but was never used routinely. Recently, 2 large trials also showed advantage with the addition of OFS to AIs as compared to OFS and tamoxifen in pre-menopausal women. Fulvestrant is another option for women with stage IV breast cancer. More recently, modulation of endocrine resistance with mammalian target of rapamycin (mTOR) inhibitor has been reported in patients with metastatic breast cancer and is being tested in other settings. This review summarizes the major advances in endocrine treatment of receptor positive breast cancer in all settings.