Chronic myelomonocytic leukaemia (CMML)
Many people are diagnosed with CMML because doctors find abnormal monocytes during a blood test for something else. Your doctor may then arrange a number of tests for you, including:
blood tests to look at how many blood cells you have and whether they are normal
a bone marrow test
Read about having a bone marrow test
Your doctor may also do tests on the bone marrow to look for changes in the of the CMML cells. Chromosomes contain the genetic material inside cells. These tests are called cytogenetics (pronounced sigh-toe gen-et-ics).
Doctors are learning more about CMML all the time. You might have other tests done on the bone marrow to look for other gene changes. You might hear this called myeloid next generation sequencing (NGS).
For most people CMML is treatable, but for most people it is not curable. They can have a good quality of life while having treatment for CMML.
The type of treatment you need depends on:
the type of CMML you have
whether you have symptoms
your age and whether you have any other medical conditions
You and your specialist discuss your treatment plan before you start.
If you have no or few symptoms you might not need treatment at first. Instead, you will have regular check ups including blood tests. You might hear this called watchful waiting or active monitoring. You also get advice on keeping well, for example information on exercise and healthy eating.
If your symptoms get worse or the disease progresses, you usually start treatment for CMML.
Most people need supportive treatment at some point. The treatment you need depends on the type of symptoms you have. You might need a combination of treatments.
You might have blood transfusions if your are low. If your are low you might require platelet transfusions, especially if you are experiencing any symptoms of bleeding.
Having a lot of blood transfusions can cause a build up of iron in your body. Red blood cells contain iron and your body stores this. But too much iron in your body can damage your heart and liver. To stop this, you might need to take medicines to get rid of the extra iron.
You might also need to take antibiotics to treat infection. And sometimes to prevent infection.
Growth factors are drugs that encourage your bone marrow to make more blood cells.
Erythropoietin is a growth factor that increases the number of red blood cells. You might have this if your red blood cell level is low.
Your nurse or doctor will give you more information about these supportive treatments.
Chemotherapy is a type of anti cancer drug treatment. The drugs work by disrupting the growth of cells and stopping them from dividing.
You can have chemotherapy as a tablet, an injection just under your skin, or as an injection into a vein. You might have just one drug or a combination of drugs.
The type of chemotherapy you have depends on your type of CMML and your general health. Chemotherapy treatments that are commonly used include:
azacytidine
hydroxycarbamide
Azacitidine is a type of drug called a hypomethylating agent. It works by switching off a protein called DNA methyltransferase. This switches on genes that stop the cancer cells growing and dividing. This reduces the number of abnormal blood cells and helps to control cell growth.
You usually have azacitidine as an injection just under your skin (subcutaneously) given by your nurse. You usually have this at the hospital.
Read more about azacitidine (Vidaza)
You might have hydroxycarbamide to help control a high white cell count. Hydroxycarbamide is one of a group of chemotherapy drugs known as anti metabolites. These drugs stop cells making and repairing DNA. Cancer cells need to make and repair DNA in order to grow and multiply.
You usually take this as an oral capsule every day.
You might have low dose cytarabine if you are not able to have hydroxycarbamide. But this treatment is not commonly used.
Cytarabine (Ara C, cytosine arabinoside)
Your nurse or doctor will give you more information about your chemotherapy and any possible side effects.
A donor stem cell transplant might be a treatment option for a few people with CMML. A donor stem cell transplant means you have a transplant using another person’s stem cells. It is called an allogeneic transplant.
This type of transplant is usually only suitable for people who:
are younger
are in reasonably good health, apart from your CMML
have a suitable donor (sibling or unrelated)
This is an intensive treatment and it has many risks. This is why it’s not suitable for everyone.
Go to more information about a donor stem cell transplant
Researchers around the world are looking at better ways to treat myeloproliferative or myelodysplastic disorders. And manage treatment side effects. These clinical trials sometimes include people who have CMML.
A study is setting up a record or ‘registry’ of information about a large number of people across Europe with blood cancers including CMML. If you take part, the team will collect information about your medical history, test results and treatments. Doctors also want to find out as much as possible about the many different types of myelodysplastic or myeloproliferative disorders and how best to treat them.
Go to Cancer Research UK’s clinical trials database if you are looking for a trial for CMML in the UK. There might not be any open trials at the moment. But you can read about the closed trials and look at trial results.
It takes time before the results are available. This is because the trial team follow the patients for a period of time and collect and analyse the results.
Talk to your specialist if there are any trials that you think you might be able to take part in.
Find a clinical trial for CMML
Coping with a rare condition can be difficult, both practically and emotionally. Being well informed about your condition and its treatment can help you to make decisions and cope with what happens.
Last reviewed: 23 Jan 2024
Next review due: 23 Jan 2027
Chronic myelomonocytic leukaemia (CMML) is a type of blood cancer. In CMML there are too many white blood cells called monocytes in the blood.
Get information on organisations and resources that can help you cope with chronic myelomonocytic leukaemia (CMML).
There are many cancer drugs and cancer drug combinations. All cancer drugs have individual side effects.
Find out about tests to diagnose cancer and monitor it during and after treatment, including what each test can show, how you have it and how to prepare.

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