Hormones help control how cells grow and what they do in the body. The hormones oestrogen and progesterone, particularly oestrogen, can encourage some breast cancers to grow.
Hormonal therapies reduce the amount of oestrogen in the body or stop it attaching to the cancer cells. They only work for women with oestrogen-receptor (ER) positive cancers.
Your cancer doctor will advise you to take hormonal therapy to reduce the risk of the breast cancer coming back. It also helps reduce the risk of getting a new breast cancer in your other breast. Sometimes hormonal therapy drugs are given before surgery to shrink a cancer and avoid a mastectomy.
You usually take hormonal therapy drugs for a number of years. For some women, this could be up to 10 years. You usually start taking them after surgery or chemotherapy.
The type of hormonal therapy you have depends on:
- whether you have been through the menopause or not
- the risk of the cancer coming back
- how the side effects are likely to affect you.
We have more information about individual hormonal therapy drugs.