Chronic Myeloid Leukaemia (CML)

About 600 people in the UK are diagnosed with CML each year. It can occur at any age but is more common in middle-aged and older people. It's rare in children.

CML usually develops very slowly, which is why it's described as a 'chronic' leukaemia. Many people don't need treatment for months or years. However, some people need to have treatment straight away.

People with CML make too many of a type of white blood cell called a granulocyte, which is why CML is sometimes called chronic granulocytic leukaemia (CGL). When examined under a microscope, the granulocytes aren't fully developed (immature). Over time, these abnormal white blood cells collect in the spleen, causing it to enlarge. They also fill the bone marrow reducing the number of normal white blood cells, red blood cells and platelets that are made.

The spleen is an organ on the left side of the tummy underneath the ribs. It produces small numbers of lymphocytes, stores blood cells, and destroys older, damaged blood cells. It's part of the lymphatic system, which also includes other lymphatic organs such as the bone marrow and the lymph nodes (glands).

Symptoms of chronic myeloid leukaemia

CML develops slowly and many people don't have symptoms in the early stages. It's often discovered by chance when a blood test is done for another reason, such as before an operation or as part of a routine health check.

If there are symptoms in the early stages of CML, they develop gradually and are usually mild. They tend to be non-specific and can easily be confused with the symptoms of more common illnesses, such as flu.

The signs and symptoms of CML can include the following:

  • Feeling tired or unwell
  • Weight loss and loss of appetite
  • Abdominal discomfort - people with CML sometimes have a feeling of fullness or tenderness on the left side of the tummy area (abdomen), which is caused by an enlarged spleen.
  • Bleeding or bruising easily - this can happen if there aren't enough platelets in the blood.
  • Sweating or a high temperature at night
  • Frequent infections - people with CML have a shortage of healthy white blood cells to fight off infections. Infections may be more severe and take longer to clear.
  • Looking pale and feeling tired or breathless - this happens when there aren't enough red blood cells and is called anaemia.
  • Bone pain - this can happen because too many white blood cells crowd the bone marrow, causing pain.
  • Enlarged lymph nodes - the lymph nodes can swell due to a build-up of leukaemia cells. They are usually painless.
  • Small bumps in the skin
  • Itching
  • Visual disturbances and headaches - these symptoms can occur because the tiny blood vessels in the eyes and brain get clogged with too many white blood cells. Sometimes an optician will notice changes to the blood vessels in the eye before there are any symptoms.

If you have any of these symptoms, it's important to see your doctor, but remember they are common to many illnesses other than CML.

*Information provided by Macmillan cancer support

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