Breast cancer is the most common cancer found in women around the world. Estrogen is a well established factor in breast cancer cell growth. Antihormonal therapy has been developed along with other treatment strategies such as surgery, radiotherapy, chemotherapy and molecularly targeted therapy to inhibit cell growth and distribution of cancer cells in patients with hormone-responsive breast cancer. The major modalities of antihormonal treatment consist of ablative and additive therapies. Ablative therapy eradicates the source of hormonal production, for instance bilateral oophorectomy. As opposed to the ablative therapy, the additive therapy inhibits the function of hormone that affects the growth of cancer cells. There are four different types of additive therapy used in breast cancer: selective estrogen receptor modulators such as tamoxifen which could be used in both premenopausal and postmenopausal patients; aromatase inhibitors, suitable for postmenopausal patients; estrogen receptor downregulators, the option for postmenopausal women after progression on prior antihormonal therapy, and ovarian shutdown and removal. Regarding tamoxifen, it has been used to reduce risk of breast cancer in high-risk women; however this is still not widespread used now. As a result, the objective of this article is to review the substantial clinical data of antihormonal therapy in patients with both early-stage and metastatic breast cancer.

Key words: breast, cancer, hormone, therapy