Goserelin (Zoladex) for breast cancer

Goserelin is known by its brand name Zoladex and is a type of hormone therapy. It is a luteinising hormone (LH) blocker. It stops the release of luteinising hormone from the pituitary gland. In women, this stops the ovaries from producing oestrogen. In men, it stops the testicles producing testosterone.

Goserelin is used to treat women who have breast cancer which has oestrogen receptors (ER positive) and who have not yet reached the menopause.

You have goserelin as an injection just under the skin of your tummy (abdomen) every 28 days. It is called a depot injection, which means that the drug is absorbed slowly into your body over the 28 days.

There is general information about hormone therapies in the cancer treatment section.

We've listed the side effects associated with goserelin below. You can use the links to find out more about each side effect. Where there is no link, please go to the cancer drug side effects section or click on search at the top of the page.

Most women have menopausal symptoms including the following side effects. More than 10 in every 100 women have one or more of these.

• Periods stopping while you are on treatment – they usually start again within 6 to 12 months of your treatment finishing, but if you are close to the age of your natural menopause, they may not come back
• Hot flushes and sweats in more than 9 out of 10 women (90%)
• Lowered interest in sex (libido)

Other common side effects include

• Headaches
• Skin rashes – these are usually mild but let your doctor know if you have a rash
• Painful joints
• Mood changes
• Bruising of the skin where you have the injection
• Goserelin may have a harmful effect on a developing baby – you should let your doctor or nurse know if there is any possibility that you may be pregnant before you start treatment. It is not a contraceptive and, even if your periods have stopped, you could become pregnant while you are having treatment. It is important to discuss contraception with your doctor or specialist nurse before you start
• Tumour flare – any symptoms caused by your breast cancer may get worse for the first couple of weeks after the first injection. This is because there is a temporary brief increase in the amount of oestrogen in the body

Between 1 and 10 in every 100 people have one or more of these.

• Vaginal bleeding – when you first start the treatment you may have vaginal bleeding as if you were having a period. It usually lasts from a few days to a month and doesn’t happen again
• Feeling or being sick is usually mild and can be controlled by anti sickness medicines
• Vaginal dryness is caused by the reduced amount of oestrogen
• Bone thinning is caused by a lack of oestrogen over a long period of time. When your bones are less dense they may break more easily. You will have a DEXA scan to check your bone density before you start treatment. Research has shown that bone density can improve once treatment with goserelin has finished

Some women may have changes in blood pressure. During treatment your blood pressure may be lower or higher than usual. Your nurse or doctor will check it regularly. Most women can carry on taking goserelin and their blood pressure goes back to normal either during treatment or when the treatment finishes.

The side effects above may be mild or more severe. A side effect may get better or worse through your course of treatment, or more side effects may develop as the course goes on. This depends on

• How many times you've had the drug before
• Your general health
• The amount of the drug you have (the dose)
• Other drugs you are having

Talk to your doctor, pharmacist or nurse about all your side effects so that they can help you manage them. You should have a contact number for your specialist nurse. You can ring them if you have any questions or problems. They can give you advice or reassure you. If in doubt, call them.

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and other over the counter remedies – some drugs can react together.