Goserelin (Zoladex)

Who might be offered goserelin?

Goserelin, also known as Zoladex, is a drug used to treat pre-menopausal women with oestrogen receptor positive primary or secondary breast cancer.

Research is looking at the best way (when and for how long) to use goserelin. Your specialist team will discuss your individual situation with you.

For women with primary breast cancer, goserelin may be given on its own or with tamoxifen. Guidance from the National Institute for Health and Clinical Excellence (NICE) recommends that women can be offered goserelin in addition to tamoxifen if they have been offered chemotherapy as part of their treatment but have chosen not to have it.

It is also possible to have goserelin before and during chemotherapy (usually within a clinical trial) to see whether this will help preserve fertility by reducing the damage to the ovaries from the chemotherapy drugs. If you would like more information please see our Fertility issues and breast cancer treatment factsheet.

Clinical trials are also looking at using goserelin alongside another group of hormone therapy drugs known as aromatase inhibitors.

Goserelin may also be used to treat pre-menopausal women with secondary breast cancer. It may be prescribed either alone or, more commonly, with other drugs, for example tamoxifen.

How does goserelin work?

Before the menopause, oestrogen is mainly produced by the ovaries. As oestrogen stimulates some breast cancers to grow, goserelin works by stopping the production of oestrogen from the ovaries.

It does this by interfering with hormone signals from the brain that control how the ovaries work. This is known as ovarian suppression. Another way of lowering the amount of oestrogen in the body is to remove the ovaries by surgery (oophorectomy) or by radiotherapy. This is called ovarian ablation.

For more information on these treatments, please read our Ovarian ablation and suppression factsheet.

How is goserelin given?

Goserelin comes as an implant (a small pellet) in a pre-filled syringe and is given as a subcutaneous (under the skin) injection. It is usually given every 28 days. The injection is given into the abdomen (tummy) and the first one is generally given at your hospital. After that it may be given by your GP, practice nurse at the surgery or at home if you can't travel.

If you have primary breast cancer, goserelin is usually given for two years, but in some cases it may be given for up to five years.

If you have secondary breast cancer, you will be given goserelin for as long as it keeps the cancer under control.

Will goserelin affect my periods?

Goserelin can cause periods to stop temporarily. They usually start again within three months to a year after the final goserelin injection is given. Some women who are approaching their natural menopause may find that their periods don’t start again after stopping treatment.

Although periods may have stopped or become irregular you could still become pregnant while you are having goserelin. So it’s important to use non-hormonal contraception such as a condom, IUD (intra-uterine devices) or diaphragm. Your GP can advise you about contraception choices.

What are the possible side effects of goserelin?

As goserelin may be given with tamoxifen or chemotherapy, it can be difficult to know which side effects are being caused by which treatment.

The most common side effects of goserelin are menopausal symptoms including hot flushes, sweats, vaginal dryness and a decrease in libido (sex drive). In most cases these symptoms improve over time. For more information about coping with menopausal symptoms see our Menopausal symptoms and breast cancer factsheet.

You may notice redness or bruising at the injection site after goserelin has been given but this should disappear within a few hours.

Less common side effects

During the first month of treatment there may be vaginal bleeding because of the withdrawal of oestrogen from your body. Headaches, depression and changes in breast size may also occur. Some women have reported experiencing weight gain, tiredness, nausea, mild skin rashes and parasthesia (tingling in fingers and toes). When first starting goserelin treatment some women notice joint pain and stiffness. This is because of the change in hormone levels and usually improves over time.

Changes in blood pressure can also occur. This can be higher or lower blood pressure than normal. This does not normally need treatment or mean that goserelin has to be stopped.

Lack of oestrogen over time can cause thinning of the bone (osteoporosis). You may be offered a bone density scan (DEXA scan) within three months of starting goserelin treatment. Recommendations about looking after your bone health will be made once the results of your scan are available. For more information see our Breast cancer treatment and the risk of osteoporosis factsheet.

If you are given goserelin to treat secondary breast cancer in the bone, you may have more pain for a short time and, in rare cases, the level of calcium in the blood may temporarily increase.

If you experience persistent troublesome side effects or have any questions about any side effects from goserelin, please talk to your specialist team.

 

Last review March 2012; next planned review 2013