Zoladex (goserelin)

This section explains briefly what Zoladex is, when it may be prescribed, how it works, what the benefits are and what side effects may occur. Zoladex is the brand name of the drug, which is used throughout this section. Most people know it by this name, although its generic (general) name is goserelin.

Page Contents

What is Zoladex?
Who might be offered Zoladex?
How does it work?
How is Zoladex given?
How long will I be on Zoladex?
Will Zoladex make my period stop?
Do I need to use contraception while using Zoladex?
What are the possible side effects of Zoladex treatment?
What shall I do if I have any concerns?
Help from Action Breast Cancer

What is Zoladex?

Zoladex is a drug used to treat breast cancer. It is a synthetic version of a natural hormone that controls how the ovaries work.
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Who might be offered Zoladex?

Zoladex is used to treat early breast cancer in premenopausal women. It is given in addition to surgery and other treatments such as chemotherapy, radiotherapy and tamoxifen. It is suitable for women who have oestrogen receptor positive tumours (breast cancers that are sensitive to oestrogen). There is a test to check if the breast cancer cells have oestrogen receptors. This will help to find out which women are likely to benefit from Zoladex. Zoladex may also be used to treat pre-menopausal women with secondary breast cancer (breast cancer that has spread to another part of the body). In this case it may be prescribed either alone or together with other types of treatments. As part of a clinical trial looking at chemotherapy and fertility, Zoladex may also be given to pre-menopausal women who have oestrogen receptor negative tumours.
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How does it work?

Zoladex works by ‘switching off’ the production of the hormone oestrogen from the ovaries. It does this by interfering with other hormones coming from the brain that control how the ovaries work. Within three weeks of starting the treatment, your oestrogen level will be lowered to a level similar to that of women after the menopause and this will carry on for as long as you are taking Zoladex. For more information about stopping the ovaries working see Action Breast Cancer’s factsheet on Ovarian Ablation.
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How is Zoladex given?

Zoladex is given as a subcutaneous (under the skin) injection into the abdomen (tummy) every 28 days. A local anaesthetic may be used but because the needle is specially designed to reduce discomfort this is not normally necessary. You will usually be given your first injection as an outpatient at the hospital. After this your GP, community or practice nurse can give the injections either in your home or at the surgery.
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How ling will I be on Zoladex?

Zoladex is usually given for between two and five years. If you have secondary breast cancer, you will be given Zoladex for as long as it keeps the cancer under control.
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Will Zoladex make my periods stop?

Your periods are likely to stop after the first or second injection of Zoladex. Most women will start their periods again within six months of their last Zoladex injection. In some cases, women may start to go through their natural menopause during treatment and will not have any periods afterwards.
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Do I need to use contraception while I'm taking Zoladex?

Zoladex is not a contraceptive and the risk of pregnancy is particularly high during initial treatment. If you are sexually active you should use nonhormonal methods of contraception (condoms, IUDs, diaphragms and femidoms) as long as you are taking Zoladex. As with any drug, it is important not to get pregnant while you are taking Zoladex because of the risk to the pregnancy and the baby.
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What are the possible side effects of Zoladex treatment?

Everyone reacts differently to drugs and some people experience more side effects than others.

The main side effects are menopausal symptoms including hot flushes, sweats and a loss of libido (sex drive). For more information see Action Breast Cancer’s factsheet on Understanding and Managing Menopausal Symptoms.

Headaches, mood changes, depression, vaginal dryness and changes in breast size may also occur. During the first month of treatment there may be vaginal bleeding because of the withdrawal of the hormone oestrogen. Occasionally there may be joint pain and stiffness, mild skin rashes and local reactions such as bruising at the injection site.

In very rare cases, high or low blood pressure may be noticed. This does not normally need treatment, but sometimes Zoladex has to be stopped. Lack of oestrogen over a long period can cause osteoporosis (thinning of the bone). If you have concerns about this, you may find it helpful to have further discussion with your specialist team.

If you are given Zoladex to treat secondary bone cancer you may have more pain for a short time, and in rare cases the level of calcium in the blood may increase. This can be monitored by checking your blood levels. If you have persistent troublesome side effects from taking Zoladex, tell your specialist team so that they can decide how best to deal with them.
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What shall I do if I have any concerns?

If you are troubled by side effects, you may find it more difficult to cope with your everyday work, home and family routines. If you have any problems whilst you are taking Zoladex it is important to discuss your concerns with your specialist or breast care nurse. You might find it easier to share your feelings with someone who has had a similar experience to you. Reach to Recovery is a programme set up to help and support women who have recently had a breast cancer diagnosis. The programme works on the principle of personal contact between the patient and a Reach to Recovery volunteer – a woman who has had treatment for breast cancer. Carefully selected and fully trained volunteers are available to provide advice and reassurance at a time when a woman is most in need of both. For more information on individual support or support groups in your area, call the Action Breast Cancer Freefone Helpline on 1800 30 90 40.
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Help from Action Breast Cancer

Action Breast Cancer is a national project established by the Irish Cancer Society to provide breast cancer information and support and to fund breast cancer research. Its services are free, confidential and accessible. For more information call the Action Breast Cancer Helpline on Freefone 1800 30 90 40 or visit www.cancer.ie
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ABC would like to thank Breast Cancer Care in the UK for their permission to adapt the text in this factsheet from their series of factsheets.