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Hormones occur naturally in the body and help control how cells grow and what they do. Female 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 blocking oestrogen from attaching to the cancer cells.They only work for women who have oestrogen-receptor positive cancers|.
Women with primary breast cancer are often prescribed hormonal therapy to reduce the risk of breast cancer coming back after their initial treatment. A different hormonal therapy is prescribed if the cancer comes back.
Hormonal therapies are often the first treatment for women with ER positive breast cancer, which has spread to other parts of the body, particularly the bones|. Some women are given chemotherapy| first then hormonal therapy afterwards. There are different hormonal treatments available so if one doesn’t work, or it stops working, others can be tried.
Hormonal therapies are usually easy to take - many are taken as tablets. Although side effects can sometimes be troublesome, they’re rarely serious. Some of the side effects of hormonal therapies are similar to symptoms of the menopause, and some treatments will cause a temporary or permanent menopause.
We have more information about breast cancer and menopausal symptoms|, which you might find useful.
You’ll need to take your hormonal therapy for a few weeks or months before your doctors can tell if it’s working.
The type of hormonal therapy your cancer specialist prescribes usually depends on whether you’ve been through the menopause or not.
After the menopause, oestrogen is no longer produced by the ovaries, but some oestrogen is still produced from hormones in the fatty tissues of the body. If you’ve been through the menopause (postmenopausal) you may be offered treatment with an:
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:
Some premenopausal women may be given treatment with tamoxifen and ovarian suppression/ablation at the same time.
Tamoxifen works by preventing oestrogen in the body from attaching to breast cancer cells and encouraging them to grow. It’s often used in premenopausal women to reduce the chance of breast cancer coming back. But it can also be effective in controlling secondary breast cancer for both pre and postmenopausal women who haven’t taken it before.
Tamoxifen is taken as a daily tablet. The side effects may include:
For many women, these side effects are mild and may reduce over time. If you continue to have problems, talk it over with your specialist nurse or doctor as there are sometimes ways of reducing the effects.
In postmenopausal women, a less common side effect of tamoxifen is that it can slightly increase the risk of blood clots in the leg or lung. Let your doctor know straight away if you have pain, warmth, swelling or tenderness in an arm or leg, or any chest pain.
Women who are prescribed tamoxifen to treat secondary breast cancer in a bone may find it makes the bone pain worse for the first few days. This is known as tumour flare. Rarely this can cause a raised level of calcium in the blood (hypercalcaemia) with symptoms of nausea| (feeling sick), vomiting and thirst.
Let your doctor know if you get these symptoms.
Fulvestrant is only used to treat postmenopausal women. It’s given as an injection once a month into a muscle in your buttock. It can be used to treat secondary breast cancer after other hormonal therapies have been used. The side effects are similar to tamoxifen.
Aromatase inhibitors (AIs) are only used in women who’ve been through the menopause. After menopause, hormones produced by the adrenal glands (small glands above the kidneys) are converted by a chemical called aromatase into oestrogen. Aromatase inhibitors stop this from happening and reduce oestrogen levels.
Anastrozole (Arimidex®), letrozole (Femara®) and exemestane (Aromasin®) are all AIs and are taken daily as a tablet. Side effects can include tiredness, joint and muscle pain, and hot flushes. Aromatase inhibitors can cause thinning of the bones (osteoporosis).
You’ll have a scan called a DEXA scan, which is short for dual energy x-ray absorptiometry scan, to assess your bone health (density) before you start taking an AI. If you’re already taking drugs to strengthen your bones (bisphosphonates|) you may not need to have this scan.
These drugs are only used in women who’ve not been through the menopause. They stop a gland in the brain (pituitary gland) from sending messages to the ovaries to produce oestrogen. Pituitary downregulators stop the ovaries producing oestrogen causing a temporary menopause.
A commonly used pituitary downregulator for women with breast cancer is goserelin (Zoladex®).| The side effects are similar to menopausal symptoms and include hot flushes and sweats, joint pain, lowered sex drive, headaches and mood changes. It’s given as a monthly injection under the skin of the tummy (abdomen).
This is occasionally done in women who’ve not been through the menopause. Stopping the ovaries from working| is done by removing them with an operation or occasionally with a short course of radiotherapy to the ovaries.
The operation can often be done during a short stay in hospital using keyhole surgery. The surgeon makes a small cut in the tummy area and inserts a long thin tube with a tiny light and camera on the end called a laparoscope. The ovaries are removed through the cut on your tummy using the laparoscope, which has surgical instruments attached to it. You usually recover quickly from this type of operation. Both approaches (surgery and radiotherapy) will bring on a permanent menopause.
When surgery is used, your periods will stop immediately.
After radiotherapy to the ovaries women usually have one more period before their periods stop completely. It’s important to use contraception for three months after radiotherapy.
It can be difficult to cope with permanent menopause when you’re already coping with secondary cancer. Our cancer support specialists| can give you more information about coping with menopausal effects.
Knowing that you’re definitely unable to have children| or add to your family can be a very emotional loss to cope with. You may find you want time to discuss the treatment with your partner, or someone close to you, before you make your decision.
If the cancer isn’t controlled by taking tamoxifen or aromatase inhibitors, drugs called progestogens, which are similar to the female hormone progesterone, may be used. They’re usually given as tablets and the commonest drugs are megestrol acetate (Megace®)| and medroxyprogesterone acetate (Farlutal®, Provera®).|
The side effects include increased appetite, weight gain, feeling sick, or slight vaginal bleeding (spotting). They can also cause breathlessness|, although this is rare. Let your doctor know if this happens.
Content last reviewed: 1 September 2010
Next planned review: 2013
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.
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© Macmillan Cancer Support 2013
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