Goserelin for breast cancer (Zoladex®)

Goserelin, also commonly called Zoladex®, is a type of hormonal therapy that is used in the treatment of prostate and breast cancers and some other conditions. This information is about Zoladex as a treatment for breast| cancer.

We have separate information about goserelin for prostate cancer|.

How Zoladex works Back to top

Hormonal therapies interfere with the production or action of particular hormones in the body. Hormones are substances produced naturally in the body. They act as chemical messengers and help to control the activity of cells and organs.

Most breast cancers need supplies of the hormone oestrogen to grow. Production of oestrogen by the ovaries is stimulated by a hormone called leuteinising hormone, which is produced by the pituitary gland in the brain.

Zoladex stops the production of leuteinising hormone from the pituitary gland, which leads to a reduction in oestrogen levels. The cancer cells then grow more slowly or stop growing altogether. The cancer may shrink in size.

How it is given Back to top

Zoladex is given by injection under the skin of the abdomen (subcutaneously). It is given as a regular injection, either every four weeks or every three months. It can be given by your GP or practice nurse at the surgery. If you are not able to visit the surgery, a district nurse can give you the injection at home. People may occasionally find the injection slightly uncomfortable, and may notice an area of redness or darker colour at the injection site afterwards.

When it may be given Back to top

Zoladex is used to treat women who have not yet had their menopause. It may 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). It may also be used to try to reduce the chance of an early breast cancer (cancer that has not spread) coming back.

Zoladex can be used alone or alongside other types of treatment. Your doctor will consider a number of different factors before deciding whether Zoladex is the most appropriate treatment for you.

Possible side effects Back to top

Each person's reaction to any medication is different. Many people have very few side effects with Zoladex, while others may experience more. We have outlined the most common side effects, so that you can be aware of them if they occur. However, we have not included those which are very rare and therefore extremely unlikely to affect you. If you notice any effects that you think may be due to the drug, but which are not listed in this information, please discuss them with your doctor or nurse.

You will see your doctor regularly while you have this treatment so that they can monitor the effects. This information should help you to discuss any queries about your treatment and its side effects with your doctor or nurse, who are in the best position to help and advise you.

Menstruation 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 age of menopause when she began the treatment, her periods may not return 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 forms of contraception while having Zoladex treatment. It is helpful to discuss this with your doctor.

Some people may have some of the following side effects:

Tumour flare There may be a temporary increase in the levels of oestrogen for the first few days or weeks of starting Zoladex. As a result, some people may find that they have an increase in symptoms, such as an increase in the size of their tumour. If you experience any problems, you will need to let your doctor know.

Hot flushes 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 people find it is helpful to cut down on tea, coffee, nicotine and alcohol. Drugs, such as certain anti-depressants in low doses, may be helpful in controlling this side effect. Your doctor or nurse can discuss this with you.

Some women have found that complementary therapies| can be helpful. Your GP may be able to give you details about obtaining these on the NHS. Let your specialist know before starting any therapy to help reduce hot flushes.

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, and these are available from a chemist or can be prescribed by your doctor. Your doctor or nurse can discuss this with you.

Skin rashes Some people have skin rashes. Let your doctor know if this occurs.

Sore joints Some people may have soreness in their joints, but this is usually mild and will stop when the treatment is finished.

Bone thinning (osteoporosis) You may be at more risk of osteoporosis if you are taking Zoladex. Your specialist will advise you on how this can be monitored or treated, if needed. Let them know if you have any discomfort in your bones or joints.

Weight gain and tiredness You may notice that you gain a few pounds in weight and may feel less energetic| than usual. This usually subsides when the Zoladex treatment is stopped.

Vaginal bleeding Some women have this during the first few weeks of taking Zoladex. It will not come back after that.

Additional information Back to top

What if I miss an injection? Delaying an injection by 2–3 days should not make a great difference. It is important to remember, however, that the benefits of the injections are designed to last either four or 12 weeks, depending on which preparation you are prescribed. You should therefore have them as regularly as possible.

Length of treatment Your doctor will discuss the length of treatment that they feel is appropriate for your situation. Zoladex is often given for two years and then stopped, but may be given for longer. Treatment with Zoladex may continue for as long as it is effective in controlling your cancer.

Contraception It is not advisable to become pregnant while taking Zoladex, as the developing foetus may be harmed. It is important to use effective contraception while you are having treatment with this drug. Again, discuss this with your doctor.

References Back to top

This section has been compiled using information from a number of reliable sources including:

• The Electronic Medicines Compendium website www.medicines.org.uk (December 2008)
• Martindale: The Complete Drug Reference (35th edition). Sweetman et al. Pharmaceutical Press, 2007.
• British National Formulary (56th edition). British Medical Association and Royal Pharmaceutical Society of Great Britain, September 2008.

For further references, please see the general bibliography|.