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Will my polycythaemia vera or ET turn into leukaemia? | CION Cancer Clinics
Most people with polycythaemia vera or essential thrombocythaemia never develop leukaemia. The chance is small but real, and it grows slowly over many years. It is higher after a change to myelofibrosis, in older age and when extra gene changes are found. Regular blood counts, spleen checks and a marrow test when needed are how any change is caught early. At CION Cancer Clinics, every leukaemia, MDS and MPN case is reviewed by our haematologist and discussed at a tumour board before a plan is agreed.
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Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
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On this page
- Will polycythaemia vera or ET turn into leukaemia?
- What kinds of change are doctors watching for?
- What raises the risk, and what does not?
- How would a change be picked up?
- What do these words on a marrow report mean?
- What do families fear that is not true?
- What can this page not tell you?
- Common questions about MPN turning into leukaemia
The short answer
Will polycythaemia vera or ET turn into leukaemia?
For most people, no. Polycythaemia vera and essential thrombocythaemia usually stay stable for many years, and most people never develop leukaemia. The chance is small but real, and it slowly adds up the longer you live with the condition.
Why the question comes up at all
Both conditions are MPNs (myeloproliferative neoplasms). That means a change in the bone marrow makes it produce too many blood cells. Doctors class MPNs as a type of chronic blood cancer, even though they behave very differently from acute leukaemia. Hearing the word "cancer" understandably makes families ask what comes next.
What your risk depends on
The chance is not the same for everyone. It tends to be higher in essential thrombocythaemia that has already changed to myelofibrosis, in older age, and when certain extra gene changes are found in the marrow. It is lower when the condition has been stable with normal-looking marrow. Your haematologist can tell you which group you fall into far better than any general figure can.
Why doctors worry more about clots day to day
For most people with an MPN, the more common and more immediate danger is a blood clot, such as a stroke, heart attack or a clot in a leg vein. That is why so much of your treatment aims to keep counts under control and protect your blood vessels. Keeping that treatment going is the most useful thing you can do while the longer-term question is watched.
This page gives no percentage on purpose. A number from a study of thousands of people does not describe you, and it can frighten more than it helps.How an MPN can change
What kinds of change are doctors watching for?
Leukaemia is not the only change, and not the most common one. These are the three your team keeps an eye on.
Change to myelofibrosis
Scar tissue slowly builds up in the marrow. Counts may fall, the spleen may grow, and tiredness increases. This is the more common change, and it often happens over years.
Change to acute myeloid leukaemia
Immature cells called blasts start to crowd the marrow and blood. This is less common. It is sometimes called blast phase, and it needs urgent specialist treatment.
Often comes after
- A period of myelofibrosis
- Many years of the condition
Change in the marrow cells
Less often, the marrow starts making faulty cells in a pattern similar to myelodysplasia. Counts drop and the cells look abnormal under the microscope.
A marrow test is needed to tell these changes apart.Not sure whether this applies to you?
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What raises the risk, and what does not?
Linked to a higher risk
Not shown to raise it
Having had the MPN for many years, and older age
Venesection, the regular removal of blood
Having already changed to myelofibrosis
Taking aspirin as advised by your team
Extra gene changes found on marrow testing
Hydroxyurea on its own, in studies so far
Some older medicines that are rarely used now
Diet, stress or everyday activity
Catching change early
How would a change be picked up?
Regular blood counts
A rising white count, a falling haemoglobin or platelet count, or needing less venesection than before can all be early clues that your team notices.
A blood smear
Looking at cells under the microscope can show blasts or teardrop-shaped red cells. These do not confirm a change, but they prompt more tests.
Your symptoms and spleen
New night sweats, weight loss, fevers without infection, bone pain or a growing spleen are reported and checked at your review.
A bone marrow test
If there are warning signs, a marrow sample with gene testing gives the answer. CION arranges this with qualified laboratories.
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On your report
What do these words on a marrow report mean?
- Blasts
- Very young blood cells. A few are normal in the marrow. A rising number is a sign your doctor takes seriously.
- Blast phase
- The MPN has changed into acute leukaemia.
- Post-PV or post-ET myelofibrosis
- Marrow scarring that has developed after polycythaemia vera or essential thrombocythaemia.
- Reticulin fibrosis grade
- How much scar-like fibre the pathologist sees in the marrow. Higher grades mean more scarring.
- Additional mutations
- Gene changes found alongside JAK2, CALR or MPL. Some carry a higher risk of change, others do not.
- Karyotype
- A test of the chromosomes in the marrow cells. Certain abnormal results raise the risk.
Commonly believed
What do families fear that is not true?
"It is a blood cancer, so leukaemia is only a matter of time."
Most people with polycythaemia vera or essential thrombocythaemia never develop leukaemia. Many live for decades with a stable condition. The label describes how the disease starts, not where it is sure to end.
"Hydroxyurea causes leukaemia, so it is safer to stop it."
Studies so far have not shown a clear rise in risk from hydroxyurea on its own. Stopping it without advice can raise the risk of clots, which is a much more common danger. Talk to your haematologist first.
"If I feel well, nothing can be changing."
Early change can show on blood counts before you feel anything. That is why regular checks matter even in good years.
"A change to leukaemia means nothing can be done."
Treatment options exist, including intensive treatment and, for some people, a stem cell transplant at a specialist centre. Suitability depends on age, fitness and the marrow findings.
Being straight with you
What can this page not tell you?
It cannot tell you your own risk. That comes from your diagnosis, how long you have had it, your counts over time, your spleen, and any marrow and gene results. Only your haematologist has all of those together.
Questions worth asking at your next review
Ask whether your condition is currently stable. Ask whether a marrow or gene test has shown anything that changes your risk. Ask which symptoms or count changes should make you call before the next visit. Ask whether your current treatment is still the right one. Writing the answers down helps family members who could not come.
Living with the worry
It is normal to think about this after every blood test. Worry does not change the risk, but regular follow-up does help catch change early. If the fear is affecting sleep or daily life, say so. Talking to a counsellor is a reasonable part of care.
Your case at CION is reviewed by the haematology team and discussed at a tumour board if a change is suspected.Questions we are asked
Common questions about MPN turning into leukaemia
Is polycythaemia vera already a type of leukaemia?
No. Polycythaemia vera is a chronic blood cancer, but it is not leukaemia. The marrow makes too many mature cells that still work. In leukaemia, immature cells crowd out normal ones. Polycythaemia vera can change into leukaemia in a small number of people, usually after many years.
Which is more likely, myelofibrosis or leukaemia?
Change to myelofibrosis is more common than change to leukaemia. When leukaemia does develop, it often follows a period of myelofibrosis. Both are watched for at your regular reviews through blood counts, spleen checks and, when needed, a marrow test.
Is essential thrombocythaemia lower risk than polycythaemia vera?
In general, essential thrombocythaemia carries a lower risk of changing to leukaemia than polycythaemia vera. Individual results vary, and your diagnosis must be confirmed properly, because some conditions that look like ET on a blood test behave differently. Your haematologist can explain your own picture.
What symptoms should make me call early?
Call your team if you notice new drenching night sweats, unplanned weight loss, fevers without an infection, bone pain, unusual bruising or bleeding, or a feeling of fullness from a growing spleen. None of these proves a change, but they should be checked before your next routine visit.
Can anything lower my risk?
No lifestyle step has been shown to prevent change to leukaemia. What helps is keeping up regular follow-up, taking your treatment as planned, and reporting symptoms early. Not smoking and staying active help protect your heart and blood vessels, which matters in any MPN.
Do I need a bone marrow test every year?
Usually not. A marrow test is often done at diagnosis and then repeated only when something changes, such as falling counts, a growing spleen or new symptoms. Your haematologist decides when one is needed and arranges it with a qualified laboratory.
If it changes, is a transplant possible?
For some people, yes. A stem cell transplant is done at specialist transplant centres and suits only people fit enough for it. It does not suit many older adults or people with other serious illnesses. CION's team can assess you and coordinate a referral if it is an option.
Should my children be tested for the same thing?
In most families, no. The gene changes behind MPNs usually develop during life and are not passed on. A few families do have more than one affected person. If that is your situation, mention it, and your haematologist will advise whether any testing makes sense.
Your Haematologist
Meet CION's haematologist. One specialist for your blood report and your plan.
Dr. Basudev Pokhrel reviews blood counts, transfusion needs and blood disorders, and works with the CION tumour board on blood cancers.
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Sources
- National Cancer Institute — Chronic Myeloproliferative Neoplasms Treatment (PDQ), Patient Version
- NHS — Polycythaemia
- Leukemia & Lymphoma Society — Myeloproliferative Neoplasms
- NHLBI — Polycythemia Vera
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Polycythaemia Vera ExplainedThe basics of the conditionHydroxyurea in MPN: What to ExpectSide effects and what the evidence saysEnlarged Spleen in MPN: What It MeansOne of the signs doctors watchMPN Monitoring: Which Tests and How OftenThe checks that catch change earlyLeukaemia guideIf you need to understand acute leukaemia
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