Leukaemia Explained

Leukaemia is a type of blood cancer that affects blood-forming cells in the bone marrow. There are several different types of leukaemia, which can behave differently and require different treatments. Here, we explain the main types of leukaemia, possible symptoms, risk factors, diagnosis and treatment.

Contents

• What is Bone Marrow?
• What are Blood Cells?
• So, What is Leukaemia?
• Factors that are known to increase the risk of Leukaemia
• What Are the Signs and Symptoms of Leukaemia?
• What Causes Leukaemia?
• How Is Leukaemia Diagnosed?
• What Treatments Are Available for Leukaemia?
• Help and Support

What is Bone Marrow?

Bone marrow is the soft, spongy tissue found inside certain bones. It plays an essential role in producing blood cells, including red blood cells, white blood cells and platelets.

What are Blood Cells?

Blood contains several different types of cells suspended in a fluid called plasma. The main types of blood cells are:

• White blood cells: These form an important part of the immune system and help the body fight infection. There are several types of white blood cell, including lymphocytes and neutrophils.
• Red blood cells: These contain haemoglobin and carry oxygen from the lungs to tissues throughout the body.
• Platelets: These small cell fragments help the blood to clot and therefore help control bleeding.

So, What is Leukaemia?

Leukaemia is a cancer of blood-forming cells. It usually begins in the bone marrow and can lead to large numbers of abnormal white blood cells being produced. These abnormal cells can interfere with the production and function of healthy blood cells.

There are several types of leukaemia. Four of the main types are:

• Acute lymphoblastic leukaemia (ALL): A fast-developing leukaemia affecting lymphoid cells. ALL is the most common type of leukaemia in children, particularly younger children, but it can also affect adults.
• Acute myeloid leukaemia (AML): A fast-developing cancer of myeloid cells. AML becomes more common with age, although it can occur in younger adults and children.
• Chronic lymphocytic leukaemia (CLL): A usually slow-developing cancer affecting lymphocytes. It mainly affects older adults and is rare in children.
• Chronic myeloid leukaemia (CML): A cancer affecting myeloid blood-forming cells. CML can occur at any age but is much more common in adults than children.

The terms acute and chronic describe how the leukaemia generally develops. Acute leukaemias can progress quickly and usually require prompt treatment. Chronic leukaemias tend to develop more slowly and, depending on the type and individual circumstances, may sometimes be monitored before treatment is needed.

Factors that are known to increase the risk of Leukaemia

In most people who develop leukaemia, it is not possible to identify a single cause. Having a risk factor does not mean that someone will develop leukaemia, and many people diagnosed with the disease have no obvious risk factors.

Risk factors also differ according to the particular type of leukaemia. Factors associated with an increased risk of some types include:

• Age: Some types of leukaemia become considerably more common as people get older, although ALL is particularly associated with children and younger people.
• Smoking: Smoking increases the risk of AML. Cancer Research UK estimates that around 3% of leukaemia cases in the UK are attributable to smoking.
• Ionising radiation: Exposure to high levels of ionising radiation can increase the risk of developing some types of leukaemia.
• Previous cancer treatment: Certain chemotherapy medicines and radiotherapy can slightly increase the risk of developing leukaemia later in life.
• Certain genetic conditions: Some inherited or genetic conditions, including Down’s syndrome, are associated with an increased risk of particular types of leukaemia.
• Certain blood disorders: Some existing disorders affecting blood cell production can increase the risk of AML.
• Benzene exposure: Long-term or high occupational exposure to benzene is associated with an increased risk of AML.

These factors affect risk rather than providing a direct explanation for an individual diagnosis. Most people exposed to a recognised risk factor will not develop leukaemia.

What Are the Signs and Symptoms of Leukaemia?

Symptoms vary according to the type of leukaemia and can develop quickly or gradually. Some people, particularly those with certain chronic leukaemias, may initially have few or no noticeable symptoms and the condition may be discovered following a blood test.

Possible signs and symptoms can include:

• Feeling unusually tired or weak.
• Pale skin.
• Frequent or persistent infections.
• A high temperature or fever.
• Unexplained bruising or bleeding, such as frequent nosebleeds or bleeding gums.
• Unexplained weight loss.
• Night sweats.
• Swollen lymph nodes or glands.
• Bone or joint pain.
• Shortness of breath.
• Loss of appetite.
• Discomfort or swelling in the abdomen, which can sometimes be caused by an enlarged spleen or liver.

These symptoms are common and can be caused by many conditions other than leukaemia. Having one or more of them does not mean that you have cancer. However, if you have persistent, unexplained or worsening symptoms, contact your GP so that they can investigate the cause.

What Causes Leukaemia?

Leukaemia develops when genetic changes occur in blood-forming cells, causing them to grow and behave abnormally. The abnormal cells can multiply and build up in the bone marrow and blood, interfering with the body’s ability to produce enough healthy red blood cells, white blood cells and platelets.

This disruption can help explain symptoms such as tiredness and pallor from anaemia, repeated infections because of abnormal white blood cells, and unusual bruising or bleeding when platelet levels are low.

Exactly why these genetic changes occur is often unknown. Leukaemia is not one single disease, and the biological changes involved vary between different types.

How Is Leukaemia Diagnosed?

If leukaemia is suspected, your GP may ask about your symptoms and medical history, examine you and arrange a blood test. A full blood count can identify unusual numbers or appearances of blood cells that may require further investigation.

If the results suggest leukaemia, you will usually be referred to a specialist in blood disorders, known as a haematologist. Further tests depend on the suspected type of leukaemia and may include additional blood tests, genetic or molecular tests, scans and a bone marrow examination.

A bone marrow biopsy or aspiration involves taking a small sample of bone marrow for laboratory examination. The sample is usually taken from the back of the hip bone. Local anaesthetic is used to numb the area, and some people may also be offered sedation depending on the procedure and their circumstances.

The results help doctors determine whether leukaemia is present and, if so, identify its type and characteristics so that the most appropriate treatment can be planned.

What Treatments Are Available for Leukaemia?

Treatment depends greatly on the type of leukaemia, its biological characteristics, the person’s age and general health, and whether they have received treatment previously. Because the different forms of leukaemia behave differently, there is no single treatment programme suitable for everyone.

Acute leukaemias generally require treatment to begin quickly. Some chronic leukaemias progress much more slowly and may not require immediate treatment. In these circumstances, specialists may recommend regular monitoring and start treatment if the disease progresses or begins to cause problems.

Treatments can include:

• Chemotherapy: Medicines that destroy cancer cells or prevent them from multiplying. Chemotherapy remains an important treatment for several forms of leukaemia, although the drugs and treatment schedules vary considerably.
• Targeted treatments: Some medicines target particular genetic changes or proteins found in leukaemia cells. Targeted treatments are especially important in the management of some types of leukaemia, including CML.
• Immunotherapy: Treatments that help the immune system recognise or attack cancer cells are used in certain circumstances and for some types of leukaemia.
• Radiotherapy: Radiotherapy is used less commonly than chemotherapy for leukaemia but may be recommended in particular situations.
• Stem cell transplant: A stem cell transplant, sometimes referred to as a bone marrow transplant, may be considered for certain patients. It allows healthy blood-forming stem cells to repopulate the bone marrow after intensive treatment.
• Supportive treatment: Treatment may also include blood or platelet transfusions, antibiotics and other medicines to manage complications, infections and side effects.

Doctors sometimes use the term remission when tests show that signs of leukaemia have substantially reduced or can no longer be detected using particular tests. Remission does not have exactly the same meaning as cure, and the outlook varies significantly between different forms of leukaemia and from person to person.

Treatment for leukaemia has improved considerably, but survival statistics cannot predict what will happen to an individual. Factors including the exact type of leukaemia, age, genetic characteristics and response to treatment can all influence a person’s outlook.

Help and Support

A diagnosis of leukaemia can be difficult for both the person affected and those close to them. Specialist UK organisations provide information, practical advice and emotional support:

• Leukaemia Care provides information and support for people affected by leukaemia, MDS and MPNs.
• Children with Cancer UK funds childhood cancer research and provides support for children, young people and their families.
• Cure Leukaemia supports research and clinical trials aimed at improving treatments for blood cancers.
• Blood Cancer UK funds research and provides information and support for people affected by blood cancer.

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