Hormone therapy

You may be advised to have hormone therapy if your breast cancer is oestrogen receptor positive (ER+). This type of breast cancer has receptors within the cell that bind to the female hormone oestrogen and stimulate the cancer to grow.

All breast cancers are tested for oestrogen receptors using tissue from a biopsy or after surgery.

When oestrogen receptors are not found (ER-) tests may be done for progesterone (another female hormone) receptors. As oestrogen receptors play a more important role than progesterone receptors, the benefits of hormone therapy are less clear for people whose breast cancer is only progesterone receptor positive (PR+ and ER-). If this is the case your specialist will discuss with you whether hormone therapy is appropriate.

If your cancer is found to be hormone receptor negative, then hormone therapy will not be of any benefit to you.

When is hormone therapy prescribed?

Hormone therapy may be prescribed in a number of situations.

• Hormone therapy is given to people with primary invasive breast cancer to reduce the risk of the breast cancer coming back (known as adjuvant treatment). It is usually started after surgery but if you are also having chemotherapy it will probably start after this is finished.
• It may also be given before surgery to reduce the size of the cancer (known as primary or neo-adjuvant treatment) or because surgery isn’t an option, for example for people who have other illnesses such as lung or heart conditions.
• Hormone therapy is used to treat local and regional recurrences and secondary breast cancer, either alone or alongside other treatments, depending on what treatments you had before. If your breast cancer comes back when you're already being treated with hormone therapy, you'll probably be offered a different type of hormone therapy.
• Trials are also looking at the role of hormone therapies in preventing breast cancer in women who are known to be at high risk of developing breast cancer.