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Hormonal therapies are treatments to reduce the levels of hormones in the body or block their effects on cancer cells. They are often given after surgery|, radiotherapy |and chemotherapy| for breast cancer to reduce the chance of the cancer coming back.
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:
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|.
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:
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.
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:
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.
Tamoxifen is the standard treatment in premenopausal women with breast cancer. It’s also used in women who have been through the menopause.
We have more information on tamoxifen|, including how it works and what the side effects are.
Tamoxifen is usually given for five years. If you’re close to your natural menopause when you start tamoxifen, after a few years when you’re postmenopausal you may be switched to an aromatase inhibitor.
Goserelin (Zoladex®) is a commonly used pituitary down-regulator for women with breast cancer. It stops the pituitary gland in the brain from sending messages to the ovaries to produce oestrogen. Pituitary down-regulators stop the ovaries producing oestrogen, causing a temporary menopause. The side effects are similar to menopausal symptoms and include:
Zoladex is given as a monthly injection under the skin of the tummy (abdomen). When the treatment is finished, the ovaries usually begin to produce oestrogen again and your periods re-start. But if you were close to your natural menopause when you started taking the drug, this may not happen.
We more information about Zoladex and breast cancer|.
Hormonal therapy reduces the risk of breast cancer coming back, so it’s important to take it for as long as your cancer specialist prescribes it.
If you’re finding the side effects difficult to cope with, tell your cancer specialist or nurse. They can prescribe drugs to help and advise you on other ways of coping. If the side effects don’t improve and are very troublesome, your cancer specialist may suggest switching to a different type of AI or to tamoxifen. And if you’re having problems with tamoxifen, you may be advised to switch to an AI.
If you find it hard to remember to take your tablet every day, it can help to build taking it into your daily routine so it becomes a habit. These tips may also help:
Content last reviewed: 1 August 2011
Next planned review: 2013
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© Macmillan Cancer Support 2013
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