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Your body produces hormones like estrogen and progesterone. These hormones are chemical substances that regulate such specific body functions as metabolism, growth and reproduction.

The normal growth and function of breast cells is stimulated by estrogen and progesterone. In about two-thirds of all breast cancer cases, progesterone and estrogen also appear to encourage the growth of most breast tumours. When you’ve had surgery, your doctor can test the level of hormone receptors in your tumour. These receptors are known as estrogen and progesterone receptors. If your tumour is positive for hormone receptors, you may be a candidate for hormone therapy.

How it works

Hormone therapy (also called "anti-estrogen therapy") is a systemic treatment that includes a number of different treatments (drugs, removal of ovaries). It’s designed to affect the level of female hormones in the body as an adjuvant therapy (treatment done after surgery) or neoadjuvant therapy (treatment done before surgery). By lowering the level of hormones in your body, the cancer cell growth is slowed down. Most women take a hormone drug as their form of hormone therapy.

Who may benefit from hormone therapy?

Studies have shown that both postmenopausal and premenopausal women benefit from hormone therapy. There are other factors that determine good candidates for this therapy such as tumour size, the presence of cancerous lymph nodes and the possibility of cancer spreading in other areas of their body. Again, these are general guidelines – you and your doctor will decide if hormone therapy is appropriate for you. Hormone therapy may also be recommended for women whose breast cancer has come back and where the breast cancer is hormone receptor positive.

Hormone therapy may also be recommended by your doctors to be used as adjuvant treatment of early breast cancer, for women who have not yet gone through menopause.