Hormonal therapy involves the manipulation of a patient’s endocrine system through the exogenous administration of gonadal steroid hormones or hormonal antagonists that inhibit the production or activity of such hormones.
Breast cells are programmed to respond to certain hormones as signals for growth and multiplication. The most prominent examples of these hormones are estrogens and progesterone. Many breast cancercells retain hormone receptors. The hormone receptors therefore make the cancerous cells responsive to these particular hormones. Most of the estrogen in women’s bodies is made by the ovaries. Estrogen makes hormone-receptor-positive breast cancers grow. So reducing the amount of estrogen or blocking its action can reduce the risk of early-stage hormone-receptor-positive breast cancers coming back (recurring) after surgery. Hormonal therapy medicines can also be used to help shrink or slow the growth of...