Goserelin for breast cancer (Zoladex®, Zoladex LA®)

Hormones are chemicals that our bodies make. Hormones act as messengers and help control how cells and organs work. Hormonal therapies are drugs that change the way hormones are made or how they work in the body.

Many breast cancers rely on the hormone oestrogen (or estrogen) to grow. This type of breast cancer is called oestrogen-receptor positive (ER positive) breast cancer. Goserelin stops the body making oestrogen. This lowers oestrogen levels, which may stop breast cancer growing, or shrink the cancer.

Goserelin is given as a very small pellet injected under the skin (subcutaneously). It is usually injected in the tummy area (abdomen). The pellet releases the drug slowly as it dissolves under the skin. 

Zoladex® is given every 4 weeks. Zoladex LA® is given every 12 weeks.

You usually have the first injection at your hospital clinic appointment. After this your practice nurse or GP can give it to you at the surgery. If you are not able to visit the surgery, a district nurse may give you the injection at home. 

Tell your doctor or nurse if you are taking any medicines to thin your blood, as this may increase bruising.

Your nurse or doctor will talk to you about your treatment plan.

The area near the injection may become:

• painful
• swollen
• red or darker. 

If this happens, let your doctor know. Painkillers may help.

You may have a local anaesthetic cream to numb the area before the injection.

Hot flushes are a common side effect of this treatment. During a flush, your neck and face may feel warm. If you have white skin, your skin may look red. If you have black or brown skin, your skin colour may deepen. Flushes can last up to 5 minutes. You might also have sweats or feel anxious or irritable during a flush. 

Here are some things you can do to reduce the effects of hot flushes:

• Wear natural fabrics, such as cotton.
• Wear layers so you can remove clothes as needed. 
• Use cotton sheets and layers of bedding you can remove. 
• Try cooling pads or pillows to keep you cool.
• Keep rooms cool or use a fan.
• Have cold drinks and avoid caffeine and alcohol. 

You might have fewer hot flushes as your body adjusts to this treatment. You could try therapies to help you cope with hot flushes, such as:

• talking therapies like cognitive behaviour therapy (CBT)
• controlled breathing exercises
• yoga
• acupuncture. 

If they do not improve, talk to your doctor. Certain drugs can help to improve hot flushes. 

Flushes usually stop a few months after treatment ends. But some people continue to have them.

This treatment can cause irregular vaginal bleeding for up to a month after the first injection. After this, periods will usually stop. If you have vaginal bleeding, tell your doctor or nurse.

Even with no periods, you can still become pregnant if you have not yet been through menopause. You need to use non-hormonal contraception to prevent a pregnancy while having goserelin. Your doctor or nurse can tell you more about this.

Monthly periods may start again when you stop goserelin treatment. But if you had a natural menopause during treatment, your periods may not come back.

You may feel low or depressed, or have mood swings, during this treatment. Talking to family and friends about how you feel might help. If mood changes last for more than a few weeks, tell your doctor, nurse or pharmacist. They can talk to you about different ways to manage low mood or depression.

If you have this treatment for cancer that has spread to the bones, you may get pain in the bones when you start taking it. Doctors call this tumour flare. Your doctor can give you treatment to help with this.

This treatment can affect your skin. It may cause a rash, which may be itchy. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using soap-free cleansers and unperfumed moisturising cream every day. 

Always tell your doctor or nurse about any skin changes. They can give you advice and may prescribe creams or medicines to help. Changes to your skin usually improve when treatment ends.

While you are having this treatment, your hair may become thinner, drier and more brittle. This is usually mild. If you are worried about this, ask your nurse for advice on hair care.

This treatment may cause headaches. If you have headaches, tell your doctor, nurse or pharmacist. They can give you advice about painkillers that may help. Tell them if the headache does not get better, or gets worse.

You may get pain in your muscles or joints. If this happens, tell your doctor or nurse. They can give you advice and painkillers or other drugs to help. Being physically active and keeping to a healthy weight may help with the pain. It can keep your joints flexible and reduce stress on them. If the pain does not get better, tell your doctor or nurse. They may talk to you about changing to a different hormonal drug.

Taking this treatment for several months or more can increase the risk of bone thinning. This is called osteoporosis. It can make you more likely to get a broken bone (fracture). 

You may have bone density scans to check your bone health before and during treatment. These scans can diagnose osteoporosis or osteopenia (low bone density) so that it can be monitored. If your scan shows osteoporosis, your doctor usually prescribes:

• drugs to protect your bones called bisphosphonates
• calcium and vitamin D supplements. 

Regular exercise where you support your body weight, like walking, running and dancing, can help look after your bones. This is called weight-bearing exercise. Other types of strength exercises are also helpful. If you have any bone thinning or the cancer is affecting your bones, get advice from your cancer team first. 

Eating a healthy diet and not smoking also helps take care of your bones.

Goserelin may cause low or high blood pressure. If you have ever had any problems with your blood pressure, tell your doctor or nurse. Let them know if you feel dizzy or have any headaches.

You may gain weight when you are having this treatment. Eating healthily and being active can help you keep to a healthy weight. Your doctor, nurse or dietitian can give you more advice.

Cancer and some cancer treatments can increase the risk of a blood clot. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:

• throbbing pain or swelling in a leg or arm
• reddening of the skin in the area – if you have black or brown skin, this can be harder to notice, but the skin might become darker
• suddenly feeling breathless or coughing.

Always call 999 if you have:

• chest pain
• difficulty breathing.

A blood clot is serious, but it can be treated with drugs called anticoagulants. These thin the blood. Your doctor, nurse or pharmacist can give you more information about preventing and treating blood clots.

Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

If you are a woman or person assigned female at birth, your doctor will advise you not to become pregnant while having this treatment. The drug may harm a developing baby.

It is important to use an effective, non-hormonal contraception during your treatment and for a few months after it finishes. Even if your periods have stopped or are irregular, you still need to use contraception. If you are not sure or have questions about contraception, talk to your doctor or nurse.

You are advised not to breastfeed while having this treatment, or for some time after treatment ends. This is because the drugs could be passed to the baby through breast milk. 

Your doctor, nurse or pharmacist can give you more information.

Some medicines can affect how this treatment works or be harmful while you are having it. Always tell your cancer doctor, nurse or pharmacist about any drugs you are taking or planning to take, such as: 

• medicines you have been prescribed
• medicines you buy in a shop, pharmacy or online
• vitamins or supplements 
• herbal drugs and complementary or homeopathic therapies
• recreational drugs – for example, cannabis.

If you need medical treatment for any reason other than cancer, always tell the healthcare professional that you are having cancer treatment. Give them the contact details for your cancer doctor or cancer team so they can ask for advice.

If you have appointments with a dentist, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.