Leuprorelin (Prostap)

Leuprorelin is a type of hormone (endocrine) therapy used to treat breast cancer in women who have not been through the menopause (premenopausal women). 

You may hear it called by its brand name Prostap.

Some breast cancers use oestrogen in the body to help them grow. These are known as oestrogen receptor positive or ER-positive breast cancers.

Before the menopause, oestrogen is mainly produced in the ovaries. Leuprorelin “switches off” the ovaries by interfering with hormone signals from the brain that control how they work.

This is known as ovarian suppression. You may also hear it called ovarian function suppression or OFS.

Leuprorelin is usually given as an injection under the skin (subcutaneously) into the fatty tissue in your upper arm, thigh or abdomen.

It can be given alone or with other hormone treatments such as tamoxifen or an aromatase inhibitor.

It can be given monthly or every 3 months.

The injection site should be varied regularly to reduce the risk of skin reactions.

You may be given this injection as an outpatient at the hospital by your breast care nurse, or at your GP practice.

You may want to make an appointment for your next dose after each injection to make sure you have it at the right time.

Missed injections

If you miss an injection, try to have it as soon as possible.

You may have breakthrough vaginal bleeding if you miss an injection, or an egg may be released from the ovary. This could result in pregnancy, and the aromatase inhibitor may stop working.

Talk to your treatment team if you miss an injection.

Leuprorelin is used as a treatment for some breast cancers.

It can be given on its own or more commonly with another hormone therapy, such as tamoxifen or an aromatase inhibitor (anastrozole, exemestane and letrozole).

Aromatase inhibitors are not used on their own as hormone therapy in premenopausal women. This is because they’re not an effective treatment while the ovaries are still making oestrogen. But they can be effective if given alongside leuprorelin.

You will have leuprorelin at least a few weeks before you start treatment with an aromatase inhibitor. This is to make sure your ovaries are “switched off”. You will continue to have leuprorelin throughout your treatment with an aromatase inhibitor to make sure the level of oestrogen in your body doesn’t increase.

You should have blood tests before starting an aromatase inhibitor to make sure the ovaries are “switched off”. These blood tests should be repeated every 3 months during treatment with leuprorelin and an aromatase inhibitor. They may also be repeated if you have breakthrough vaginal bleeding during this treatment.

For some women there may be a small extra benefit of having an aromatase inhibitor over tamoxifen. However, there are different side effects to consider when making a choice that can affect your quality of life.

Your treatment team will discuss with you what treatment they recommend and why.

Primary breast cancer

If you have primary breast cancer, you will have leuprorelin for up to 5 years.

Metastatic breast cancer

If you have metastatic breast cancer, you’ll have leuprorelin alongside other treatment for as long as your treatment team feels you are benefitting from it and any side effects are manageable.

Chemotherapy can cause damage to the ovaries. This can reduce the number and quality of eggs and affect your ability to become pregnant (fertility) when your treatment has finished.

Whether your fertility is affected after chemotherapy depends on:

• The type of drugs used
• The dose given
• Your age
• What your fertility was like before breast cancer treatment

Some studies have shown that using hormone therapy drugs like leuprorelin to suppress the ovaries may protect them during chemotherapy.  This is because leuprorelin temporarily “shuts down” the ovaries.

Only monthly leuprorelin can be used to try to preserve fertility in premenopausal women who are having chemotherapy. You’ll normally have an injection 2 weeks before starting chemotherapy, then every month while you’re having chemotherapy.

If you want to try to preserve fertility during chemotherapy, discuss this with your treatment team before starting chemotherapy.

Like any drug, leuprorelin can cause side effects. Everyone reacts differently to drugs and some people have more side effects than others. These side effects can usually be managed and those described here will not affect everyone. 

As leuprorelin can be given in addition to chemotherapy or other hormone therapies, it’s sometimes difficult to know which side effects are being caused by which treatment.

If you’re worried about any side effects, regardless of whether they’re listed here, talk to your chemotherapy nurse or treatment team.

Common side effects

Menopausal symptoms

The most common side effects of leuprorelin are menopausal symptoms such as:

• Hot flushes
• Night sweats
• Vaginal dryness
• A decrease in sex drive (libido)
• Difficulty sleeping

Although these symptoms may be quite intense in the beginning, they usually improve over time.

Talk to your breast care nurse if menopausal symptoms are affecting your quality of life.

Breast tenderness

Breast tenderness is a common side effect of leuprorelin. 

Redness or bruising at the injection site

You may notice an area of redness or bruising at the injection site.

This should disappear within a few hours. Occasionally, bruising may be there for a few days.

Low mood and depression

Some people experience low mood or depression when taking leuprorelin.

Talk to your GP or treatment team about how to manage a change in mood. Counselling, mindfulness and regular exercise can be helpful.

Your GP or treatment team can refer you for counselling or may suggest you take an antidepressant drug. Your breast care nurse may also be able to help or tell you about support services in your local area.

Find out more about coping with breast cancer emotionally. 

Muscle and joint pain

You may have joint pain and stiffness when you first start leuprorelin. This is because the levels of oestrogen in your body have been reduced. It usually improves over time, but talk to your treatment team if it continues.

Mild pain relief like paracetamol or an anti-inflammatory drug such as ibuprofen can usually help muscle and joint pain. Before using anti-inflammatory pain relief, ask your treatment team about the correct dose, how long you should use it for and any possible side effects, especially if you have other health conditions.

Find out more about joint and muscle pain during breast cancer treatment.

Weight changes

If you lose your appetite, you may find eating small frequent meals or snacks helps keep up your food intake.  

If your appetite increases, it may affect your weight. Leuprorelin can sometimes cause fluid retention, which may also affect weight.

If you struggle to maintain a healthy weight, ask your GP about weight management services in your area.

Find out more about diet and breast cancer treatment.

Extreme tiredness (cancer-related fatigue)

Fatigue is extreme tiredness that doesn’t go away with rest or sleep. It’s a very common side effect of breast cancer treatment and may affect you physically and emotionally.

Find out more about fatigue and how to manage it.

Headaches, nausea and dizziness

Leuprorelin can sometimes cause headaches, feeling sick (nausea) and dizziness. 

These usually improve or become easier to manage over time. Mild pain relief such as paracetamol may help with headaches.

If you feel dizzy, avoid driving. If dizziness and headaches do not go away, see your GP. 

Other possible side effects

Thinning of the bone (osteoporosis)

Lack of oestrogen over a long period of time can cause osteoporosis, a condition where bones lose their strength and are more likely to break.  

Your treatment team may suggest a DEXA (dual energy X-ray absorptiometry) scan to check bone density before or after you start leuprorelin.

Find out more about looking after your bones.

If you’re concerned about your risk of developing osteoporosis, talk to your treatment team.

You can find out more information about osteoporosis and bone health on The Royal Osteoporosis Society website.

High blood pressure and high cholesterol 

Leuprorelin can cause high blood pressure in some people. Your GP will be able to monitor and treat this if necessary. 

It may also cause the level of cholesterol in the blood to rise, although this doesn’t usually need treatment. If you have a history of high cholesterol, discuss this with your treatment team or GP.

High levels of blood sugar

Leuprorelin can raise your blood sugar levels.

Signs of high blood sugar levels include:

• Feeling thirsty
• Needing to pee more often
• Feeling tired
• Losing weight

Tell your GP or treatment team if you have these symptoms.

Liver changes

Leuprorelin can occasionally cause changes to how the liver works.

These changes are usually very mild and unlikely to cause any symptoms. Your liver function will usually go back to normal once you finish your treatment

Will leuprorelin affect my periods?

You may have some vaginal bleeding at the beginning of treatment with leuprorelin. If this continues, tell your treatment team. This may mean your ovaries may not be “switched off” effectively.

After your leuprorelin injections, your oestrogen will be lowered to a level similar to that of a postmenopausal woman. Your periods should stop. This effect is usually temporary and will only last for as long as you’re having leuprorelin.

When you stop having leuprorelin, your ovaries will usually start to produce oestrogen again. Most women’s periods will start again within 3 to 12 months of finishing treatment. However, if you’re approaching the age of natural menopause, your ovaries may not start working again and your periods may not return.

Contraception while taking leuprorelin

You’re advised not to become pregnant while you’re having leuprorelin. This is because the drug could harm a developing baby.

It’s possible to become pregnant while having leuprorelin, even if your periods have stopped or become irregular.

Use a non-hormonal method of contraception to avoid getting pregnant, such as condoms, Femidoms or a diaphragm.

It may also be possible to use a coil (IUD or intrauterine device), Check with your treatment team as not all types are suitable for women with breast cancer.

Breastfeeding

Leuprorelin is not suitable while breastfeeding. This is because there’s a chance the drug could be passed on through breast milk.

Stopping injections

Stopping monthly injections

When you stop monthly leuprorelin injections, you will need to stop taking the aromatase inhibitor within 1 month of the last leuprorelin injection.

Stopping 3-monthly injections

After you have stopped 3-monthly leuprorelin injections, stop taking the aromatase inhibitor within 3 months.

Join our online forum to meet other people going through treatment at the same time as you.

You can also speak to our specialist nurses on our helpline. See below for more information.