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Essential thrombocythaemia (ET)

Essential thrombocythaemia (ET) is a type of blood cancer where your body makes too many blood cells called platelets.

In this section:

What is ET (essential thrombocythaemia)?

When you have ET, your body starts making too many blood cells called platelets.

Platelets stick together to stop you bleeding if you have a cut or a bruise, but if you have too many, it can cause blood clots which raise your risk of problems like heart attack or stroke. Treatment can control this risk.

ET is classed as a blood cancer because it involves cells (in this case, platelets) growing out of control. It's one of a group of blood cancers called myeloproliferative neoplasms.

About 2,700 people in the UK are diagnosed with ET every year. There are around 13,000 people currently living with it in the UK.

Finding out you have ET

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Causes of ET

ET is caused by certain genetic changes that happen during a lifetime. The genes most commonly affected are called JAK2, CALR and MPL. Knowing which gene is affected gives doctors more information about what will happen in the future (your prognosis).

ET is more common in people over 50 years old, and slightly more common in women.

Prognosis for ET

Treatment can’t cure ET, but it aims to lower your risk of blood clots and the problems these can bring. It also aims to control any symptoms you may have, so you can live as normal a life as possible.

There is a chance that ET can develop into another type of blood cancer. The risk is low, but talk to your hospital team if you are worried about this or anything else to do with your prognosis (what will happen in the future).

Symptoms of ET

There's a range of typical symptoms you may have if you have ET. However, you may not have any symptoms at all when you're diagnosed. Common symptoms include:

  • headaches
  • dizziness
  • visual changes
  • difficulty concentrating
  • tiredness
  • unusual bruising or bleeding
  • pain in your stomach area
  • burning pain in the feet, hands, arms, legs, ears or face.

Because ET can cause blood clots (thrombosis), it's also important to be aware of the symptoms of a blood clot.

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Tests for ET

You will have tests to confirm the diagnosis if doctors suspect you have ET. If you do have ET, you will need regular tests to monitor the ET and your risk of blood clots.

Usually, these tests will be simple blood tests. In certain circumstances, you may need an ultrasound scan or a bone marrow biopsy, but not everyone will have these.

Treatment for ET

The main aim of treatment for ET is to lower the risk of blood clots.

If your risk of blood clots is low, you may be given a low daily dose of aspirin and monitored regularly.

If your risk is higher, you may be given drugs to reduce the number of platelets in your blood.

There's a range of drugs available to treat ET and doctors will recommend the one that's best for you, based on your age, your risk level and the number of platelets in your blood.

As with all drugs, there may be some side effects, so tell your doctor if you notice any changes in how you feel. They can help with medicines and self-help advice.

Looking after yourself with ET

Lifestyle factors don't cause ET, but there may be changes you can make which will help you feel better, both physically and mentally. Drinking plenty of fluids, eating a balanced diet and keeping active may help manage symptoms and improve your general wellbeing. If you are a smoker, it's a good idea to stop if you can.

It's also important to look after your mental health. We have more information to help you find what works for you.

If someone you love has been diagnosed with ET

If your family member or friend has been diagnosed with ET, you might find our information for family and friends helpful. It covers how to support someone with blood cancer, practical tips, coping with your own emotions, and real stories from other friends and family members.

You may also want to try our podcast for family and friends, Blood Cancer Heart to Heart, featuring honest conversations between people who know what it's like to have a loved one diagnosed with blood cancer.

ET research and clinical trials

Many people find hope in the knowledge that scientists are researching better and kinder treatments for ET and other MPNs. Find out more about our MPN research: visit our research project page and select "myeloproliferative neoplasms (MPN)" in the conditions filter.

Thank you to Consultant Haematologists Clare Kane and Mallika Sekhar for checking the medical content of our ET information, and to Clinical Nurse Specialists Jodie Nightingill and Madeleine Ward for their guidance and support.

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