Chronic Myelomonocytic Leukemia Cmml

Overview

CMML is a rare type of blood cancer. It starts in the bone marrow — the soft tissue inside your bones where blood cells are made. The long name breaks down like this: 'chronic' means it usually grows slowly, 'myelomonocytic' means it affects two families of white blood cells (myeloid cells and monocytes), and 'leukemia' means cancer of the blood-forming cells. In CMML, the bone marrow makes too many of these white blood cells, and they do not work properly. At the same time, the marrow struggles to make enough healthy red blood cells (which carry oxygen) and platelets (which help blood clot). Doctors sometimes describe CMML as sitting between two groups of blood conditions: myelodysplastic syndromes, where the marrow makes too few healthy cells, and myeloproliferative neoplasms, where the marrow makes too many.

No, it is rare. Most general doctors see only a few cases in their whole career. Because it is uncommon, you will usually be looked after by a specialist blood doctor called a haematologist.

CMML is mostly diagnosed in adults over 60, and it is slightly more common in men than in women. It is unusual under the age of 40 and extremely rare in children. It can affect anyone of any background.

Symptoms

Common symptoms

• Tiredness and weakness that does not get better with rest
• Shortness of breath when walking or climbing stairs
• Pale skin, or looking 'washed out'
• Frequent or repeated infections, such as chest or urine infections
• Mild fever or night sweats
• Bruising or bleeding more easily than usual, such as nosebleeds or bleeding gums
• Tiny red or purple dots on the skin (called petechiae) caused by small bleeds under the skin
• Feeling full or uncomfortable on the left side of the belly, from an enlarged spleen
• Unexplained weight loss
• Itching skin, mouth ulcers or swollen gums
• A general sense of feeling unwell

Symptoms in children

• CMML itself is extremely rare in children. A similar but separate condition called juvenile myelomonocytic leukemia (JMML) can affect babies and young children.
• Signs in young children may include poor feeding, irritability, a rash, a swollen belly, frequent infections and slowed growth.
• Children with these kinds of blood conditions are cared for by specialist children's cancer teams, so ask your child's doctor to refer you if you are worried.

Symptoms in older adults

• Tiredness or breathlessness may be put down to getting older, so it is easy to miss at first.
• Repeated infections or slow recovery from infections can be an early clue.
• People may notice they bruise more easily or bleed for longer after a small cut.
• An enlarged spleen can cause early fullness when eating or discomfort on the left side of the belly.
• Many older adults also have other health conditions, such as heart or kidney problems, which the specialist team will take into account when planning care.
• The disease often grows slowly in older adults, and a period of 'watch and wait' with regular blood tests is common.

Causes

Main causes

• CMML happens because of changes (variants or mutations) in the genes of blood-forming cells in the bone marrow. These changes build up during a person's life and are not usually inherited.
• These gene changes make the bone marrow produce too many white blood cells that do not mature properly, and not enough healthy red cells and platelets.
• In most people, doctors cannot point to a single cause.

Risk factors

• Getting older — the risk rises clearly after age 60
• Being male
• Previous treatment with chemotherapy or radiotherapy for another cancer
• Long-term exposure to high levels of certain chemicals, such as benzene, usually through work
• Smoking may increase the risk of some blood cancers
• Rarely, some inherited bone marrow conditions can raise the risk

When to see a doctor

See a doctor urgently if:

• You have a fever with shivering or shaking chills
• You have bleeding that will not stop
• You are suddenly much more breathless, even at rest
• You have new severe pain or swelling in your belly

Book a routine appointment if:

• You have been unusually tired for weeks and rest is not helping
• You keep getting infections, or infections take a long time to clear
• You bruise or bleed more easily than you used to
• You have lost weight without trying
• You feel full quickly or uncomfortable on your left side after eating
• You have night sweats or itching skin that does not settle

Diagnosis

CMML is diagnosed by a specialist blood doctor (haematologist). It usually starts with a routine blood test showing unusual numbers of white cells, red cells or platelets. The doctor then looks at a sample of your blood under a microscope and checks your bone marrow, because CMML can only be confirmed by finding particular patterns of cells and gene changes in the marrow. Other conditions that cause similar blood test results are also checked for and ruled out.

Tests that may be done

• A full blood count — a blood test that measures red cells, white cells and platelets
• A blood film — a drop of blood looked at under a microscope to see the shape and type of cells
• A bone marrow biopsy — a small sample of marrow taken, usually from the hip bone, using a needle and a local numbing medicine
• Genetic and molecular tests on the blood or marrow, to look for particular gene changes
• Tests to check your liver, kidneys and general health before treatment decisions
• Sometimes a scan, such as an ultrasound, to check the size of your spleen

What to expect at your appointment

A bone marrow biopsy can be uncomfortable for a few seconds and the area may ache for a day or two afterwards. Results usually take from a few days to a couple of weeks, because the genetic tests take longer than the cell tests. Waiting for results can be an anxious time, so it can help to take someone with you to appointments and write down your questions. Your haematologist will explain what the results mean for you, including how slowly or quickly the condition is likely to behave, and what the options are.

Treatment

There is no single 'best' treatment for CMML — the right plan depends on your age, your general health, your blood counts, the gene changes found, and how much the condition is affecting your daily life. Some people are monitored with regular blood tests for months or years without needing treatment. Others need treatment to control blood counts, ease symptoms or reduce the risk of infections and bleeding. Your team will review your plan regularly, because CMML can change over time.

Self-care at home

• Keep a simple diary of symptoms, temperatures and how you feel, so you can share patterns with your team
• Wash your hands often and ask visitors who are unwell to stay away for a while
• Take care of your teeth and gums, and tell your team about mouth ulcers
• Eat a balanced diet with plenty of fluids, and follow food hygiene advice from your team
• Build rest into your day, and break activities into smaller chunks
• Stay gently active — short, regular walks are often better than one big effort
• Check with your haematology team before starting new supplements, herbal remedies or over-the-counter medicines
• Avoid contact sports or activities where you could bruise or bleed easily if your platelet count is low

Medical treatments

Treatment is grouped into a few broad approaches. Supportive care means managing symptoms and keeping you safe: blood transfusions to top up red cells or platelets, antibiotics to treat infections, and medicines that encourage the bone marrow to make more red blood cells. Some people are given medicines (as tablets, injections or a drip) that help lower very high white blood cell counts or help control the disease and reduce the need for transfusions. For a small number of people — usually younger and fitter patients — a stem cell transplant from a donor can offer a chance of long-term control or cure, and the team will explain the risks and benefits carefully. Clinical trials are also an option and can give access to newer treatments. Your haematologist will discuss which approach suits you; this article does not recommend any specific medicine.

When is surgery considered?

Surgery is not usually part of treating CMML. Very occasionally, the spleen becomes so large and uncomfortable that an operation to remove it is discussed, but this is uncommon. A stem cell transplant involves a long stay in hospital and intensive treatment, but it is not a traditional operation.

Living with this condition

Many people with CMML live for years with a good quality of life, seeing their haematology team for regular blood tests and check-ups. Some need no treatment for long stretches; others have transfusions or medicines on a schedule. It helps to plan around your appointments, keep a list of your medicines and blood counts, and tell your team early about new symptoms. Carry a card or note saying you have a blood condition, in case you need medical care elsewhere.

Lifestyle tips

• If you smoke, stopping is one of the most helpful things you can do — ask your doctor or pharmacist for support
• Keep alcohol within your country's recommended limits, or ask your team what is right for your liver and blood counts
• Try to keep a regular sleep routine and protect time for rest
• Keep up with dental check-ups and tell your dentist about your diagnosis
• Use sun protection, as some medicines can make skin more sensitive to the sun
• Ask your team about travel, vaccinations and insurance before booking a trip

Diet and exercise

There is no special diet that treats CMML, but eating well helps you cope with treatment and infections. Aim for a varied diet with fruit, vegetables, whole grains, protein and plenty of fluids. If your white cell count is low, your team may give food hygiene advice, such as washing produce well and avoiding unpasteurised foods. Gentle, regular movement — walking, light housework, stretching — helps with fatigue, mood and strength. Build up slowly, rest when you need to, and check with your team before starting anything strenuous, especially if your blood counts are low.

Mental health and emotional wellbeing

A rare cancer diagnosis can bring shock, fear, sadness and worry, and it is common to feel anxious before check-ups. Fatigue can also affect mood. These feelings are normal and worth talking about — with your team, a counsellor, or people you trust. If you ever have thoughts of harming yourself or feel you cannot cope, please contact your local emergency number or a crisis support service right away. You do not have to manage alone.

Prevention

CMML cannot usually be prevented, because it is caused by gene changes inside blood-forming cells that happen unpredictably during life. Not smoking and limiting contact with harmful chemicals such as benzene are sensible general steps for your health, but they do not guarantee anything.

Vaccines

Your haematology team may recommend routine vaccinations, such as flu and pneumonia jabs, and will advise on COVID-19 vaccination. Some vaccines, particularly 'live' vaccines, may not be safe when your immune system is weakened or during certain treatments. Always check with your haematology team before having any vaccine, including travel vaccines.

Screening programmes

There is no national screening programme for CMML. For most people, the condition is found when a blood test is done for another reason. If you have a close relative with a rare inherited bone marrow condition, mention this to your doctor.

Complications

If left untreated

• Worsening anaemia, causing heavy tiredness and breathlessness
• More frequent or more serious infections
• Bleeding or bruising from low platelet counts
• An enlarged spleen, which can cause discomfort and early fullness when eating
• In a minority of people, the disease can change into a faster-growing type of leukemia called acute myeloid leukemia (AML)
• Lower quality of life from ongoing fatigue and repeated hospital visits

Long-term outlook

CMML affects each person differently. Many people live for years with the condition, sometimes needing little treatment at first, and are supported by regular monitoring and good supportive care. In some people, the disease changes over time, including in a minority who develop a faster-growing leukemia, and the team will watch for this. Treatments continue to improve, and clinical trials are testing new approaches. Your haematologist can talk through what is known about your particular pattern of blood counts and gene changes, and what to expect.

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