Chronic myeloid leukaemia

Page last reviewed: 13/07/2011

Leukaemia is cancer of the white blood cells. Symptoms of leukaemia include:

  • pale skin
  • tiredness
  • breathlessness
  • repeated infections over a short space of time

Chronic leukaemia means that the condition progresses slowly over the course of many years and no immediate treatment is required

Bone marrow

All of the blood cells in your body are produced by bone marrow. Bone marrow is a spongy material found inside the bones. It is important because it produces special cells called stem cells.

Stem cells are very useful because they have the ability to create other specialised cells that carry out important functions. The stem cells in bone marrow produce three important types of blood cells:

  • red blood cells, which carry oxygen around the body
  • white blood cells, which help fight infection
  • platelets, which help stop bleeding

In leukaemia, the cancer begins in the stem cells and causes them to produce more white blood cells than are needed. Over time, the cancerous white blood cells build up, disrupting the normal balance of cells in the blood.

This means that the body does not have enough red blood cells or platelets. This can cause symptoms of anaemia, such as tiredness, as well as increasing the likelihood of excessive bleeding.

Also, as the white blood cells are not properly formed, they are less effective at fighting bacteria and viruses, making you more vulnerable to infection.

Types of chronic leukaemia

Chronic leukaemia is classified according to the type of white blood cells that are affected by cancer. There are two main types of white blood cell:

  • lymphocytes - which are mostly used to fight viral infections
  • myeloid cells - which perform a number of different functions, such as fighting bacterial infections, defending the body against parasites and preventing the spread of tissue damage 

There are two main types of acute leukaemia that are related to the two main types of white blood cells. They are:

  • chronic lymphocytic leukaemia - which is cancer of the lymphocytes
  • chronic myeloid leukaemia - which is cancer of the myeloid cells

These pages focus on chronic myeloid leukaemia (CML). For information on chronic lymphocytic leukaemia.

How common is chronic myeloid leukaemia?

Chronic leukaemia is an uncommon type of cancer.There are on average 33 people diagnosed in Ireland with Chronic Myeloid Leukemia(CML) every year.

CML is more common in people aged 40-60. There is no evidence that it runs in families.

Chronic leukaemia can be cured using a bone marrow transplant. However, this is not suitable for everyone.

Outlook

The outlook for CML depends to a large extent on how well a person responds to treatment with a new type of medication called tyrinase kinase inhibitors However ,bone marrow transplant may be used for patients who do not respond to this treatment.. For people who respond well, the outlook is good, and it has been estimated that they may have a normal life expectancy.

Bone marrow

Bone marrow is the soft, spongy tissue in the centre of bones that produces blood cells.

Blood

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Acute

Acute means occuring suddenly or over a short period of time.

Chronic

Chronic usually means a condition that continues for a long time or keeps coming back.

Stem cells


Stem cells are cells that are at an early stage of development, so they still have the ability to turn into any type of cell in the body.

Oxygen


Oxygen is an odourless, colourless gas that makes up about 20% of the air we breathe.

Platelets


Platelets are cells in the blood that control bleeding by plugging the broken blood vessel and helping the blood to clot.

Bacteria


Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some are good for you.

Tissue


Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.

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There are three stages of chronic myeloid leukaemia (CML), which are outlined below.

  • Chronic - the number of cancerous blood cells in your blood remains low and there are very mild or no symptoms.
  • Accelerated - the number of cancerous blood cells in your blood begins to increase at a faster rate, your symptoms will gradually get worse and you will be more vulnerable to infection.
  • Advanced - the number of cancerous blood cells in your blood is dangerously high, symptoms will be severe and you will be very vulnerable to infection. The advanced stage of CML is also known as a blast crisis.

The symptoms of CML during the condition's chronic or accelerated stage include:

  • tiredness
  • loss of appetite
  • weight loss
  • anaemia(fewer red blood cells)
  • increased sweating
  • abnormal or unusual bruising and bleeding
  • bone pain
  • haedaches and visual disturbances
  • loss of appetite
  • tenderness and swelling on the left side of your abomen,due to an enlarged spleen
  • night sweats and fever

CML can also cause swelling in your spleen (an organ that helps to filter impurities from your blood). This can cause a lump to appear on the left side of your abdomen, which may be painful when touched. A swollen spleen can also put pressure on your stomach, causing a lack of appetite and indigestion.

The symptoms of CML in its advanced stage will be much more noticeable and troublesome. They include:

  • repeated infections in a short space of time, due to the lack of healthy white blood cells
  • unusually pale skin, due to the lack of red blood cells
  • bleeding, such as nose bleeds, bleeding gums, or unusually heavy periods (in women), due to the lack of platelets (blood-clotting cells)
  • easily bruised skin
  • swollen lymph nodes (glands)
  • itchy skin

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Genetic mutation

Chronic leukaemia begins with an alteration to the structure of the DNA found in the stem cells that are responsible for producing white blood cells. The DNA provides the cells with a basic set of instructions, such as when to grow and reproduce. The alteration that occurs to the DNA's structure is known as a genetic mutation.

The mutation in the DNA changes the instructions which causes the stem cells to produce more white blood cells than are needed. The white blood cells are also produced too quickly and, over time, they begin to lose their infection-fighting properties.

Eventually, the increase in the number of affected white blood cells will lead to a corresponding decrease in red blood and platelets. The reduction in the other blood cells is an underlying cause for many of the symptoms of chronic leukaemia.

Possible triggers for chronic leukaemia

What triggers the development of chronic leukaemia and causes the initial mutation in stem cells is unknown. The one proven risk factor is exposure to radiation.

However, radiation is only a significant risk if the levels are extremely high, such as those recorded after an atomic bomb explodes, or those released after a nuclear reactor accident, such as the one at Chernobyl.

Benzene

There is limited evidence that prolonged exposure to the chemical benzene leads to an increased risk of chronic myeloid leukaemia (CML). Benzene is found in petrol and is also used in the rubber industry, but there are strict controls to protect people from prolonged exposure.

Benzene is also found in cigarettes. However, it is thought that smoking is more of a risk factor in acute leukaemia than it is in chronic leukaemia.

Occupational risks

There are a number of occupations that have been linked to an increase risk of chronic leukaemia, possibly due to exposure to certain substances such as pesticides or chemicals.

These occupations include:

  • all types of agricultural workers
  • people who are involved with rubber or plastic manufacture
  • tailors and dressmakers
  • cleaners
  • builder's labourers

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Blood tests

Suspected cases of chronic leukaemia are usually first detected after a blood test, which has often been carried to diagnose another, unrelated condition.

A blood test that reveals abnormally high levels of white blood cells could be a sign of chronic leukaemia. If you have a blood test with abnormal results, you will be referred to a haematologist (a specialist in treating blood conditions) for further testing.

Bone marrow biopsy

To confirm a diagnosis of chronic leukaemia, the haematologist will take a small sample of your bone marrow to examine under a microscope. This procedure is known as a bone marrow biopsy. A bone marrow biopsy is usually carried out under a local anaesthetic.

The haematologist will numb an area of skin at the back of your hip bone, before using a needle to remove the bone marrow sample. The procedure can be uncomfortable and you may experience some bruising and discomfort for a few days afterwards. It takes around 15 minutes to complete and you should not have to stay in hospital overnight.

The bone marrow sample will be checked to see if there are cancerous cells. If there are, the biopsy will also be able to help determine which type of chronic leukaemia is present.

Further tests

There are a number of additional tests that can be used to help reveal more information about the progress and extent of the leukaemia, which can also provide an important insight into how the leukaemia should be treated. These are outlined below.

Cytogenetic testing

Cytogenetic testing involves identifying the genetic make-up of the cancerous cells. There are a number of specific genetic variations that can occur during leukaemia and knowing what these variations are can have an important impact on treatment.

For example, 90% of people with chronic myeloid leukaemia (CML) have an altered gene, known as the Philadelphia chromosome. People who have this altered gene are known to respond well to a medicine called imatinib.

Lymph node biopsy

If you have been diagnosed with chronic leukaemia, further biopsies may be carried out on any enlarged lymph nodes that you have. These are to see how far the leukaemia has spread.

CT scans

If you have chronic leukaemia, a computerised tomography (CT) scan may be used to check that your other organs, such as your heart and lungs, are healthy.

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Your treatment plan

As chronic leukaemia is a complex condition, it is usually treated by a team of different healthcare specialists working together. This type of team is known as a multidisciplinary team (MDTs).

Members of your MDT may include:

  • a haemato-oncologist (a specialist in the non-surgical treatment of leukaemia using techniques such as chemotherapy)
  • a haemato-pathologist (a specialist in the study of cancerous blood cells)
  • a pharmacist
  • a social worker
  • a psychologist
  • a specialist cancer nurse (who will serve as the first point of contact between you and the other members of the MDT)
  • a counsellor

There are several factors that will need to be taken into account when deciding on your treatment. They include:

  • your age
  • the extent of your cancer
  • the likely progression of your cancer
  • the possible side effects of treatment

No one will rush you into making a decision about your treatment, and you are free to talk to as many people as you want to, including your partner, family and friends.

Many people find that it can be helpful to write a list of questions at home to ask the MDT. Your MDT will be able to recommend what they feel are the best treatment options for you, but ultimately the decision will be yours.

The treatment of chronic leukaemia when the condition is in its early stages will depend on what type of chronic leukaemia you have. However, the treatments for both chronic myeloid leukaemia (CML) and chronic lymphocytic leukaemia in their advanced stage are more or less the same.

Early-stage chronic myeloid leukaemia (CML)

Imatinib

A medicine called imatinib is the main treatment that is recommended for CML. It is usually given as soon as a diagnosis is made because the medicine is designed to slow the progression of CML, and to prevent the condition reaching the accelerated or advanced phase.

Imatinib is a type of tyrosine kinase inhibitor. This means that it blocks a protein called tyrosine kinase (tyrosine kinase helps to stimulate the growth of cancer cells). This reduces the production of abnormal white blood cells.

Imatinib is taken orally (as a tablet). The side effects of imatinib are usually mild and should improve with time. They include:

  • nausea
  • vomiting
  • swelling in the face and lower legs
  • muscle cramps
  • rash
  • diarrhoea
  • fatigue

Alternatives to imatinib

It is estimated that 10-40% of people who take imatinib become resistant to its effects, so an alternative treatment is required. Two new medications that can be used as an alternative to imatinib are:

  • nilotinib
  • dasatinib

Both medications work in a similar way to imatinib in that they block the effects of proteins that help stimulate the growth of cancer cells.

Side effects of nilotinib include:

  • vomiting
  • abdominal pain
  • bone and joint pain
  • dry skin
  • loss of appetite
  • hair loss
  • insomnia
  • night sweats
  • dizziness
  • tingling or numbness

Common side effects of dasatinib include:

  • diarrhoea
  • headache
  • a rash or red, dry, itchy skin
  • a build-up of fluids in the body, such as around your legs or face
  • fatigue
  • breathlessness
  • nausea
  • bone and muscle pain

If the side effects become particularly troublesome, temporarily stopping the treatment usually helps to bring them under control. Treatment can then be resumed, possibly using a lower dose of medication. 

Dasatinib can also lead to a sudden drop in the number of blood cells, which means that you will become vulnerable to infection and you will bruise and bleed more easily.  

Bone marrow and stem cell transplants

The aim of treating CML is to keep the disease well controlled. If other treatments have not worked,bone marrow transplant may be beneficial and offered.

The only available cure for chronic leukaemia is to have a bone marrow or stem cell transplant.

Psychological effects of chronic leukaemia

You may find it useful to talk to other people who are living with leukaemia. Your GP or multidisciplinary team may be able to provide you with details of local support groups.

You may find it useful to speak with someone at the Irish Chronic Myeloid Leukaemia Patient Support group.  Their webpage is www.irishcmlgroup.org

Deciding against treatment

As many of the treatments that are described in this section have unpleasant side effects that can affect your quality of life, you may decide against having a particular type of treatment.

This is entirely your decision and your MDT will respect any decision that you make. Pain relief and nursing care will be made available as and when you need it.

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Immunocompromised

Being immunocompromised (having a weakened immune system) is a common complication of chronic leukaemia. There are two reasons for this:

  • The lack of healthy white blood cells means that your immune system is less able to fight infection.
  • Many of the medicines used to treat chronic leukaemia can weaken the immune system.

This means that you are more vulnerable to developing an infection, and that any infection you have has an increased potential to cause serious complications.

You may be advised to take regular doses of antibiotics to prevent infections occurring. You should immediately report any possible symptoms of an infection to your GP or care team because prompt treatment may be required to prevent serious complications.

Symptoms of infection include:

  • high temperature (fever) of 38C (101.4F) or above
  • headache
  • aching muscles
  • diarrhoea
  • tiredness

Avoid contact with anyone who is known to have an infection, even if it is a type of infection that you were previously immune to, such as chickenpox or measles. This is because your previous immunity to these conditions will probably be suppressed (lowered).

While it is important to go outside on a regular basis, both for exercise and for your psychological wellbeing, avoid visiting crowded places and using public transport during rush hour.

Also ensure that all of your vaccinations are up-to-date. Your GP or care team will be able to advise you about this. You will be unable to have any vaccine that contains activated particles of viruses of bacteria such as:

  • the mumps, measles and rubella (MMR) vaccine
  • the polio vaccine
  • the oral typhoid vaccine
  • the BCG vaccine (used to vaccinate against tuberculosis)
  • the yellow fever vaccine

Infertility

Many treatments used to treat chronic leukaemia can cause infertility. In some cases, infertility may be permanent.

Your multidisciplinary team will be able to provide a good estimation of the risk of infertility in your specific circumstance.

It may be possible to take steps to guard against any risk of infertility before beginning treatment. Men can have samples of their sperm stored so that it can be used to implant an embryo. Similarly, women can have fertilised embryos stored, which can then be placed back into the womb after treatment.

Psychological effects of chronic leukaemia

Receiving a diagnosis of chronic leukaemia can be very distressing, particularly if it is unlikely that your condition can be cured. At first, the news may be difficult to take in.

The situation can be made worse if you are confronted with the knowledge that even though your leukaemia may not currently be causing any symptoms, it could be a serious problem in later life. Having to wait many years to see how the leukaemia develops can be immensely stressful and can trigger feelings of anxiety and depression.

If you have been diagnosed with leukaemia, talking to a counsellor or psychiatrist (a doctor who specialises in treating mental health conditions) may help you to combat feelings of depression and anxiety. Antidepressants or medicines that help to reduce feelings of anxiety may also help you cope better with the condition.

You may find it useful to talk to other people who are living with leukaemia. Your GP or multidisciplinary team may be able to provide you with details of local support groups.

You may also find it useful to speak with someone at the Irish Chronic Myeloid Leukaemia Patient Support group.  Their webpage is www.irishcmlgroup.org
 

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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