Goserelin for breast cancer (Zoladex ®)
Goserelin is a type of hormonal therapy that is used to treat breast cancer. In this section we refer to it by its more commonly used name, Zoladex ®.
The section describes Zoladex, how it’s given and some of its possible side effects. It should ideally be read with our general information about breast cancer.
You will see your doctor regularly while you have this treatment so they can monitor its effects. This section should help you discuss any queries about your treatment and its side effects with your doctor or specialist nurse.
Zoladex is a hormonal therapy used to treat prostate cancer, breast cancer and some other conditions. This information is about Zoladex as a treatment for breast cancer.
Hormones are substances produced naturally in the body. They act as chemical messengers and help control the activity of cells and organs. Hormonal therapies interfere with the production or action of particular hormones in the body.
Some breast cancer cells have receptors, which allow particular types of hormones to attach to the cancer cell. Many breast cancers rely on the hormone oestrogen to grow. They are known as oestrogen-receptor positive or ER-positive breast cancers.
Oestrogen is produced by the ovaries. Its production is stimulated by a hormone called luteinising hormone, which is produced by the pituitary gland in the brain. Zoladex stops the production of luteinising hormone from the pituitary gland, which leads to a reduction in oestrogen levels. The cancer cells then grow more slowly or stop growing altogether, and the cancer may shrink in size.
Zoladex is given by injection under the skin of the abdomen (subcutaneously). It’s given as a regular injection every four weeks.
It can be given by your GP or practice nurse at the surgery. If you're not able to visit the surgery, a district nurse can give you the injection at home. You may find the injection slightly uncomfortable and notice an area of redness or darker colour at the injection site afterwards. You may have a local anaesthetic cream applied before the injection to reduce any discomfort.
Zoladex is used to treat women who have not yet had their menopause. It may be used after surgery for oestrogen-receptor positive early breast cancer to reduce the chance of the cancer coming back. It may also be used to slow and control the growth of breast cancer in women whose breast cancer has spread to other parts of the body (advanced or metastatic cancer).
Your doctor will consider a number of different factors before deciding whether Zoladex is the most appropriate treatment for you. It can be used alone or alongside other types of treatment.
Length of treatment with Zoladex
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Your doctor will discuss with you the length of treatment they feel is appropriate for your situation. Zoladex is often given for two years, but may be given for longer.
Treatment with Zoladex may continue for as long as it’s effective in controlling your cancer.
Possible side effects of Zoladex
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Each person's reaction to any medicine is different. Some people have very few side effects while others may experience more. We have outlined the most common side effects but haven't included those that are rare and therefore unlikely to affect you. If you notice any effects that aren't listed here, discuss them with your doctor or nurse.
You may have some of the following side effects, to varying degrees:
Change in periods
Women taking Zoladex usually find that their periods stop while they are having treatment. This is an expected effect and is due to the lowered levels of oestrogen in the body. When the Zoladex is stopped, periods will usually start again. However, if a woman was nearing the menopause when she began the treatment, her periods may not come back when the treatment stops.
Although periods usually stop while you are having treatment, Zoladex is not a contraceptive drug. Women need to ensure that they use effective contraception while having Zoladex treatment. You can discuss this with your doctor or nurse.
There may be a temporary increase in oestrogen levels for the first few days or weeks of Zoladex treatment. The size of the tumour may temporarily increase, which is called tumour flare. As a result, you may find that you have an increase in symptoms. Let your doctor know if this causes you any problems.
These can be quite common. Many women find that the hot flushes wear off after a period of time. There are a number of ways to help reduce or control hot flushes and sweats. Some women find it helps to cut down on tea, coffee, nicotine and alcohol. Drugs, such as low doses of some antidepressants, may help to control this side effect. Your doctor or nurse can discuss this with you.
Some women find complementary therapies, such as acupuncture, helpful. Your GP may be able to give you details about getting these on the NHS. Let your specialist know before starting any therapy to help reduce hot flushes.
We have more information about treatments for menopausal symptoms.
Diane shares her experience of coping with menopausal symptoms after treatment for breast cancer.
Loss of sex drive (libido)
Many women experience a lowering of their sex drive while having treatment with Zoladex. The loss of libido normally continues for as long as the treatment is given. Some women also have vaginal dryness. Lubricating gels can help to counteract the dryness - these are available from a pharmacist or your doctor can prescribe them. Your doctor or nurse can discuss this with you.
Some people have skin rashes. Let your doctor know if this occurs.
Some people may have soreness in their joints, but this is usually mild and will stop when treatment finishes.
Bone thinning (osteoporosis)
You may be more at risk of osteoporosis if you are taking Zoladex. Your specialist will advise you on how this can be monitored or treated. Let them know if you have any discomfort in your bones or joints.
You may experience mood swings. Talk to your doctor if this continues.
Weight gain and tiredness
You may notice that you gain weight and feel less energetic than usual. This usually improves when hormonal treatment stops.
Some women have some vaginal bleeding during the first few weeks of taking Zoladex. Let your doctor know if it continues.
Always let your doctor or nurse know about any side effects you have. There are usually ways in which they can be controlled or improved.
Additional information about Zoladex
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Missing an injection
Delaying an injection by 2–3 days should not make a great difference. But it's important to remember that the benefits of the injections are designed to last for four weeks, so you should have them as regularly as possible.
It’s not advisable to become pregnant while taking Zoladex, as it may harm the developing baby. It's important to use effective contraception while you’re having treatment with this drug.
If you’re admitted to hospital for a reason not related to the cancer, it’s important to tell the doctors and nurses looking after you that you are having hormonal treatment. You should tell them the name of your cancer specialist so they can ask for advice.
It’s a good idea to know who you should contact if you have any problems or troublesome side effects when you’re at home.
This information has been compiled using information from a number of reliable sources, including:
British National Formulary. 64th edition. 2012. British Medical Association and Royal Pharmaceutical Society of Great Britain.
electronic Medicines Compendium (eMC) (accessed September 2012).
Sweetman, et al. Martindale: The Complete Drug Reference. 37th edition. 2011. Pharmaceutical Press.
With thanks to: Bruce Burnett, Teacher Practitioner in Clinical Pharmacy Practice; and the people affected by cancer who reviewed this edition. Reviewing information is just one of the ways you could help when you join our Cancer Voices Network