Hormonal therapies for breast cancer

Hormones exist naturally in the body. They help to control how cells grow and what they do in the body. Hormones, particularly oestrogen, can encourage some breast cancer cells to grow.

Hormonal therapies work by lowering the level of oestrogen in the body, or by preventing oestrogen from attaching to the cancer cells. They only work for women who have oestrogen-receptor positive cancers|.

Hormonal therapies are given to reduce the chance of breast cancer coming back and to protect the other breast. They can work in different ways and are usually given for a number of years. You’ll start hormonal therapy after you have finished chemotherapy| (if you’re having it). Hormonal therapies can also be used before surgery to shrink a large cancer to avoid the need for a mastectomy|.

Hormonal therapies are usually well-tolerated. Sometimes side effects are more troublesome in the first few months but get better over time. If you continue to have problems, talk them over with your specialist nurse or doctor, as there are ways of reducing some of the effects. 

The type of hormonal therapy you have usually depends on:

• whether or not you’ve been through the menopause
• the risk of the cancer coming back
• how side effects of the drugs are likely to affect you.

Your cancer specialist will explain which drug or drugs and the length of time they’re given for is best in your situation.

We have more information about individual hormonal therapy drugs|. 

Hormonal therapy for women who are postmenopausal Back to top

After the menopause, oestrogen is no longer produced by the ovaries, but is still produced from hormones in the fatty tissues of the body. If you’ve been through the menopause, you may be treated with:

• an aromatase inhibitor such as anastrozole (Arimidex®), letrozole (Femara®) or exemestane (Aromasin®).
• the anti-oestrogen drug tamoxifen and an aromatase inhibitor (one type is given after the other)
• tamoxifen.

If you have a small (less than 2cm) low-grade cancer that hasn’t spread to the lymph nodes, you may be prescribed tamoxifen alone for five years. Women taking tamoxifen for 2–3 years may be switched to exemestane or anastrozole for 2–3 years. If the cancer was in the lymph nodes you may be prescribed tamoxifen for five years followed by letrozole for a few years.

Hormonal therapy for women who are premenopausal Back to top

Before the menopause, oestrogen is mainly produced by the ovaries. If you haven’t been through the menopause, you may be offered hormonal treatment with:

• the anti-oestrogen drug tamoxifen
• a pituitary down-regulator drug, such as goserelin (Zoladex®), to stop the ovaries from producing oestrogen (ovarian suppression)
• surgery to remove the ovaries (ovarian ablation)
• a combination of tamoxifen with either Zoladex or ovarian ablation (this may be an option for women who don’t want to have chemotherapy).   

In premenopausal women, some hormonal treatments bring on a temporary or permanent menopause. Women who have an early menopause will have a scan called a DXA (dual-energy x-ray absorptiometry) scan to assess their bone health.

If you’re at risk of bone thinning (osteoporosis|), your cancer specialist may prescribe drugs called bisphosphonates to protect your bones. You will probably also be advised to take calcium and vitamin D supplements to help with your bone strength – your cancer specialist can tell you more about this.