Essential thrombocythaemia
Also known as:
- ET
- Essential thrombocythemia
- Essential thrombocytosis
- Primary thrombocytosis
What is essential thrombocythaemia?
Essential thrombocythaemia is a rare and chronic blood cancer where the body produces too many platelets in the bone marrow.
In rare cases, it can develop into acute myeloid leukaemia or myelofibrosis.
How rare is essential thrombocythaemia?
The number of people diagnosed each year with ET will be between 1.5 and 3 cases per 100,000.
Who does essential thrombocythaemia affect?
Essential thrombocythaemia mainly affects people over the age of 60 but can occur at any age. It is more common in women than men with two women diagnosed for every man.
Essential thrombocythaemia can develop into other cancers
For some people, essential thrombocythaemia can lead to scarring of the bone marrow. This is called myelofibrosis.
In rare cases, ET can develop into acute myeloid leukaemia (AML), although this happens in less than 5% of people who have ET.
Why is RareCan interested in essential thrombocythaemia?
RareCan is working to accelerate research into essential thrombocythaemia by making it easier for researchers to connect with people who have this rare and chronic form of cancer. You can help us do this by becoming a RareCan member and sharing information with us about your diagnosis. We will then get in touch with you about any research opportunities that might be suitable for you.
Looking for a different cancer type?
Please visit our ‘rare cancer list’ to search for your cancer type
Useful links
If you have essential thrombocythaemia and are looking for support, we recommend the following websites:

Blood Cancer UK
Blood Cancer UK is a community dedicated to funding research and support for those affected by blood cancers like essential thrombocythaemia.
Leukaemia Care
Leukaemia Care is a UK-based charity dedicated to giving information, advice and support to anyone affected by blood cancer.





