Types of breast cancer hormone therapy
This page tells you about hormone therapy for primary breast cancer. You can find information about
Types of breast cancer hormone therapy
The female hormones oestrogen and progesterone affect the growth of some breast cancer cells. This means that drugs or treatments that block the effects of hormones, or lower the levels of oestrogen and progesterone, can be used to treat some types of breast cancer. You may have hormone therapy before or after surgery, or to treat breast cancer that has come back.
After surgery is the most common time to have hormone therapy. Hormone treatment has been proven to reduce the risk of breast cancer coming back. You usually take it for 5 years.
Hormone therapy is only likely to work if the breast cancer cells have oestrogen receptors. If they don’t, your specialist may suggest you have chemotherapy after surgery instead of hormone therapy.
Types of hormone therapy
There are three types of hormone therapy. These are called tamoxifen, aromatase inhibitors (eg Arimidex) and pituitary down regulators (eg Zoladex). Each works in a slightly different way. Which one is best for you depends mainly on whether or not you have had your menopause.
Hormones are substances that occur naturally in the body, where they control the growth and activity of normal cells. The female hormones oestrogen and progesterone are naturally produced by the ovaries before menopause. After the menopause, oestrogen is made in much smaller amounts by small glands above the kidneys, called the adrenal glands. Oestrogen can stimulate the growth of some breast cancer cells. This means that drugs or treatments that block the effects of hormones, or lower the levels of oestrogen and progesterone, can be used to treat some types of breast cancer.
Hormone therapy is only likely to work if the breast cancer cells have oestrogen receptors (ER). These are areas that allow the oestrogen to lock onto the cell. If your cancer cells don't have these receptors, your specialist may suggest that you have chemotherapy after surgery instead of hormone therapy. There is more about hormone receptors in this section of CancerHelp UK.
You may have hormone therapy to treat breast cancer
- Before breast surgery
- After breast surgery
- That has spread or come back after it was first treated
You may have hormone therapy to shrink a cancer in the breast before surgery. This can mean that you need a smaller operation than you otherwise would. It may mean you can have just the cancer removed, rather than needing the whole breast removed (a mastectomy).
This is the most common time to have hormone therapy for breast cancer. It has been proven to lower the risk of breast cancer coming back. You have the treatment for some years after your diagnosis. Exactly how long depends on the treatment you are having. You usually have hormone therapy prescribed for 5 years.
One advantage of hormone treatments is that hormones are very safe and although side effects can occasionally be troublesome, they are rarely serious.
There are several types of hormone drugs used for primary breast cancer including
Although women who have had their menopause do not produce oestrogen from their ovaries, a small amount is produced by the adrenal glands (small glands above the kidneys). Aromatase inhibitors block this oestrogen from being made. So these drugs are used for women who've had their menopause. You take them as tablets once a day. There is information below about
Aromatase inhibitors for early breast cancer
The aromatase inhibitors anastrozole, exemestane and letrozole can be used to treat women with early breast cancer, who have had their menopause. They are given after surgery and other treatment and aim to reduce the chance of the cancer coming back. Aromatase inhibitors are also used for breast cancer that has spread.
Anastrozole (Arimidex) has been tested after surgery for early breast cancer. In one trial (the ATAC trial) anastrozole was compared to tamoxifen. The trial showed that anastrozole was more likely to stop breast cancer coming back than tamoxifen. In women whose cancer did come back, it came back later in the women on anastrozole than it did in the women taking tamoxifen. There were also fewer secondary cancers and a significant reduction in the number of women who went on to get breast cancer in the other breast. Anastrozole generally has fewer side effects than tamoxifen, although it is more likely to cause joint pain or bone fractures. There is more about the ATAC trial results in the breast cancer questions section.
Another trial (the IES trial) compared tamoxifen followed by exemestane (Aromasin) for 5 years, with tamoxifen only for 5 years. The women in this trial all took tamoxifen for 2 to 3 years and then half of them switched to exemestane and the other half stayed on tamoxifen. The results showed that switching to exemestane lowered the risk of the cancer coming back more than staying on tamoxifen. You can read more about the IES trial results in the breast cancer questions section.
Another aromatase inhibitor, letrozole (Femara), has been tested and licensed for early breast cancer. One clinical trial showed that cancer was slightly less likely to come back in women who had letrozole after 5 years of tamoxifen, compared to women who finished tamoxifen and had no further treatment. The letrozole is usually given for 4 years, unless the cancer comes back before that. You may also have letrozole before surgery to try to shrink your cancer so that you can have a smaller operation to remove it.
In February 2009, The National Institute for Health and Clinical Excellence (NICE) recommended anastrozole or letrozole as a first line hormone treatment for women after surgery if
- They have ER positive breast cancer
- They have been through the menopause
- Their doctors think there is more than a low risk of the cancer coming back
If you cannot take an aromatase inhibitor for any reason, then your doctor should offer you tamoxifen. If you are going to have chemotherapy for early breast cancer, you will usually start hormone therapy once your chemo has finished.
If you have already been taking tamoxifen for 2 to 3 years, NICE recommend that you should be offered exemestane or anastrozole.
If you have already been taking tamoxifen for 5 years, and you had cancer in your lymph nodes when you had your operation, NICE recommend that you are offered letrozole for another 2 to 3 years.
Your doctor should discuss with you which treatment is most suitable for you. And they should take into account factors such as the side effects and benefits of each different hormone therapy, whether you've already had treatment with tamoxifen, and what they think the risk of your cancer coming back might be. You can find out more about the side effects of each type of hormone therapy by clicking on the links above for each particular drug.
Aromatase inhibitors to prevent breast cancer
Another major trial is looking at anastrozole as a way of preventing breast cancer in women at high risk of the disease. This trial, called IBIS 2, will be listed on our clinical trials database while it is open and recruiting women in the UK. Choose 'breast' from the drop down menu of cancer types.
Tamoxifen is a hormone treatment developed over thirty years ago. It prevents oestrogen from going in to breast cancer cells. So it lowers the risk of breast cancer coming back (recurring) after treatment. It can also help to reduce the risk of cancer in the other breast by 40%. Tamoxifen comes as tablets and is also called Nolvadex. There is detailed information about the benefits and side effects of tamoxifen on the next page of this section.
Research trials have shown that taking tamoxifen greatly improves survival rates of women with oestrogen receptor positive breast cancer. You can find up to date results from the Early Breast Cancer Triallists Group on the Clinical Trial Service Unit and Epidemiological Studies Unit website. These are written for researchers and specialists so are not in plain English. Doctors now use tamoxifen mainly for women who have not yet had their menopause or for postmenopausal women after a few years of aromatase inhibitor treatment. If you are also going to have chemotherapy for early breast cancer, you will usually start tamoxifen once your chemo has finished.
Research is currently looking into whether tamoxifen might help to prevent breast cancer from developing in women who have a high risk of getting breast cancer. This research is going on in several different countries around the world. Early results have been contradictory and so it is too soon to tell whether tamoxifen can help prevent breast cancer. The latest trial results publicised raise the question of side effects. Tamoxifen may prevent breast cancer, but we need to be sure that this doesn't cause too many additional medical problems for otherwise healthy women.
Another type of hormone treatment which can be used for premenopausal women is to stop the ovaries from working with particular drugs or to remove the ovaries, so that they do not produce oestrogen. This is called 'ovarian ablation'. If you have not yet had your menopause, and you have ER positive breast cancer, you will usually be offered tamoxifen hormone therapy, and possibly chemotherapy. The chemotherapy will often stop your ovaries working, but not always. If your doctor suggests chemotherapy, but you decide not to have it, they should offer ovarian ablation instead. Ovarian ablation includes
These are also called LHRH analogues. LHRH stands for 'luteinising hormone releasing hormone'. It blocks a hormone in the brain that stimulates your ovaries to make and release oestrogen.
These drugs stop your ovaries working, so you won't have periods or release eggs while you are having the injections. But this is reversible. When you stop taking the drug, your ovaries should start working again. But, if you are close to the age at which your menopause would naturally start, your ovaries may not start working again after this type of treatment. So it can tip you into an early menopause.
The most common of these drugs is goserelin (Zoladex). You have Zoladex as an injection once a month. You are likely to have menopausal symptoms, such as hot flushes and mood changes while you are having Zoladex. There is also a risk that your bones will become thinner. You should have a 'DEXA scan' to check your bone density before you start this treatment. There is information on ways of coping with menopausal symptoms in the section on living with breast cancer.
Researchers are looking into the role of ovarian ablation and chemotherapy for premenopausal women. In May 2007, the journal The Lancet published a review of the research into LHRH analogues. The reviewers found that switching off the ovaries with an LHRH analogue may be an alternative to chemotherapy for women with hormone sensitive breast cancer which has a low risk of coming back. There are ongoing trials to find out more about the role of ovarian ablation in treating breast cancer. There is more information about these trials in our research page in this section.
If you don't like the idea of a monthly injection, another option, which is permanent, is to have your ovaries removed in an operation. This will cause a sudden menopause and menopausal symptoms. There is information about how to cope with menopausal symptoms in the living with breast cancer section of CancerHelp UK.
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