What is goserelin (Zoladex®, Zoladex LA®)?

Goserelin is a hormonal therapy drug. It is also called Zoladex® or Zoladex LA®. It is used to treat breast cancer.

It is best to read this information with our general information about hormonal therapy and breast cancer.

Your cancer team will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.

This information is for anyone of any sex having goserelin as part of treatment for breast cancer. Goserelin can also be used to treat prostate cancer. We have separate information about goserelin for prostate cancer.

More information about this treatment

This information is correct at time of publishing. But sometimes the types of cancer this treatment is used for, or treatment side effects, may change between revision dates.

You can talk to your cancer team if you want more detailed information about this treatment. Or visit the electronic Medicines Compendium (eMC) website, which has patient information leaflets (PIL) for individual drugs.

How goserelin works

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

Many breast cancers rely on the hormone oestrogen 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.

How goserelin is given

You have goserelin as a small pellet (implant) that is injected under the skin (subcutaneously) in the tummy area. The pellet releases the drug slowly as it dissolves under the skin.

During your treatment, you will meet someone from your cancer team, such as a:

  • cancer doctor
  • specialist nurse
  • specialist pharmacist.

This is who we mean when we mention doctor, nurse or pharmacist in this information.

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.

If you are taking any medicines to thin your blood, tell your doctor, nurse or pharmacist. These medicines can make you bruise more easily.

You may have goserelin with other cancer drugs. Your cancer team will discuss your treatment plan with you.  

They may give you other medicines to take home. Take all your medicines exactly as they tell you to. Do not stop taking any of your medicines unless your doctor tells you to.

Injection site

The skin in the area that was injected may become:

  • painful
  • swollen
  • red, if you have white skin
  • darker, if you have black or brown skin.

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

About side effects

We explain the most common side effects of this treatment here. We also include some that are less common.

You may get some of the side effects we mention, but you are unlikely to get all of them. And you may have some side effects, including rarer ones, that we have not listed here. 

Other cancer treatments may cause different side effects. If you are also having other cancer treatment, you may have other side effects.

When you have this treatment, you will have regular appointments with a doctor, nurse or pharmacist. Always tell them about any side effects you have. They can give you: 

  • drugs to help control most side effects 
  • advice about managing side effects. 

Most side effects can be managed. But sometimes side effects are harder to control. It is important not to stop taking hormonal therapy without telling your doctor. If side effects cannot be managed, your doctor may suggest a different type of hormonal therapy.

Serious and life-threatening side effects

Some cancer treatments can cause serious side effects. Sometimes, these may be life-threatening. Your doctor, nurse or pharmacist can explain the risk of these side effects to you.

Contact the hospital

Your doctor, nurse or pharmacist will give you 24-hour contact numbers for the hospital. If you feel unwell or need advice, you can call at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

Very common side effects

These side effects happen to 10 or more people in every 100 people (10% or more) who have this treatment.

Hot flushes and sweats

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.

Vaginal dryness

This treatment can cause vaginal dryness and a lower sex drive. Non-hormonal creams, gels or lubricants may help with vaginal dryness and discomfort. You can buy these from a chemist, or your doctor can prescribe them. We have more information about cancer and sex.

Erection problems

It is common to lose your sex drive during treatment with hormonal therapy. This can cause erection problems. Things may return to normal after you stop taking the drug. But some people continue to have problems after treatment is over. Your doctor can prescribe treatments to help with erection problems. But these treatments will not increase your sex drive.

Breast swelling or tenderness

You may get swelling and tenderness of your breast tissue. Talk to your doctor or nurse if this is a problem.

Skin changes

This treatment can affect your skin. It may cause spots (acne). Sometimes 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. 

Other side effects

These side effects happen to less than 10 in 100 people (less than 10%) who have this treatment. Some of them are much rarer than this but they are still important to know about. Rare means a side effect that happens to less than 1 in 1,000 people (less than 0.1%).

Mood changes

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.

Bone thinning (osteoporosis)

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.

Vaginal bleeding and effects on periods

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.

Hair thinning

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.

Headaches

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.

Blood pressure changes

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

Raised blood sugar levels

This treatment can raise your blood sugar levels and increase the risk of diabetes. 

Signs of raised blood sugar include:

  • feeling thirsty
  • needing to pass urine (pee) more often than usual
  • feeling more tired than usual. 

Tell your doctor or nurse if you have these symptoms. They can do tests to check your blood sugar level and give you advice.

If you already have diabetes, your blood sugars may be higher than usual. You may need to check them more often, or make changes to your diabetic treatment. Your diabetic doctor or nurse will talk to you about how to manage this.

Muscle or joint pain

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.

Tingling in your fingers or toes

This treatment may cause changes in sensation in the hands and feet. This is usually mild. Tell your doctor or nurse if you have this.

Weight gain

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.

Effects on the heart

This treatment can sometimes affect how the heart works. You may have tests to check how your heart is working.

If the treatment is causing heart problems, your doctor may change the type of treatment you are having.

Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment: 

  • breathlessness
  • dizziness
  • changes to your heartbeat
  • swollen feet and ankles.

Other conditions can cause these symptoms, but it is important to get them checked by a doctor.  

Always call 999 if you have:

  • chest pain, pressure, heaviness, tightness or squeezing across the chest
  • difficulty breathing.

Tumour flare

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.

High calcium levels in the blood

If you have goserelin to treat breast cancer that has spread to the bones, sometimes it may cause high calcium levels in the blood (hypercalcaemia). This is not common. Signs of this include:

If you have any of these symptoms, contact the hospital straight away on the 24-hour number.

Other information

Blood clot risk

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.

Contraception

Your doctor, nurse or pharmacist will advise you not to get pregnant while having this treatment. The drug may harm a developing baby. It is important to use contraception to prevent pregnancy. Follow their advice about:

  • what types of contraception to use, for example using barrier contraception instead of hormonal contraception like the oral pill
  • how long after treatment you should continue to use contraception.

Fertility

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.

Breastfeeding

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.

Other medicines

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: 

Medical and dental treatment

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.

About our information

This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.

Date reviewed

Reviewed: 01 August 2024
|
Next review: 01 August 2026
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

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