Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia is a type of cancer that affects the white blood cells. It progresses rapidly and aggressively and requires immediate treatment. Both adults and children can be affected.

Acute lymphoblastic leukaemia is very rare, with around 650 people diagnosed with the condition each year in the UK. Half of all cases diagnosed are in adults and half in children.

Although rare, acute lymphoblastic leukaemia is the most common type of childhood leukaemia. About 85% of the cases that affect children occur in those younger than 15 (mostly between the ages of two and five). It tends to be more common in males than females.

Acute lymphoblastic leukaemia is different to other types of leukaemia, including acute myeloid leukaemia, chronic lymphocytic leukaemia and chronic myeloid leukaemia.

What happens in acute lymphoblastic leukaemia

All of the blood cells in the body are produced by bone marrow, a spongy material found inside bones.

Bone marrow produces specialised cells called stem cells, which have the ability to develop into 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

Normally, bone marrow doesn't release stem cells into the blood until they are fully developed blood cells. But in acute lymphoblastic leukaemia, large numbers of white blood cells are released before they are ready. These are known as blast cells.

As the number of blast cells increases, the number of red blood cells and platelet cells decreases. This causes the symptoms of anaemia, such as tiredness, breathlessness and an increased risk of excessive bleeding.

Also, blast cells are less effective than mature white blood cells at fighting bacteria and viruses, making you more vulnerable to infection.

Symptoms of acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia usually starts slowly before rapidly becoming severe as the number of immature white blood cells in your blood increases.

Most of the symptoms are caused by the lack of healthy blood cells in your blood supply. Symptoms include:

• pale skin
• feeling tired and breathless
• repeated infections over a short space of time
• unusual and frequent bleeding, such as bleeding gums or nosebleeds
• high temperature (fever) of 38C (100.4F) or above
• night sweats
• bone and joint pain
• easily bruised skin
• swollen lymph nodes (glands)
• abdominal pain – caused by a swollen liver or spleen
• unexplained weight loss 
• a purple skin rash (purpura)

In some cases, the affected cells can spread from your bloodstream into your central nervous system. This can cause a series of neurological symptoms (related to the brain and nervous system), including:

• headaches 
• seizures (fits)
• vomiting
• blurred vision
• dizziness

When to get medical advice

If you or your child has some or even all of the symptoms listed above, it's still highly unlikely that acute leukaemia is the cause. However, see your GP as soon as possible because any condition that causes these symptoms needs prompt investigation and treatment.

Read more about diagnosing acute lymphoblastic leukaemia.

What causes acute lymphoblastic leukaemia?

It is a genetic change (mutation) in the stem cells that causes immature white blood cells to be released into the bloodstream.

It's not clear what causes the DNA mutation to occur, but known risk factors include:

• previous chemotherapy – if you've had chemotherapy to treat unrelated cancers in the past, your risk of developing acute lymphoblastic leukaemia is increased; the risk relates to certain types of chemotherapy medicine (etoposide, mitoxantrone, amsacrine and idarubicin), and how much treatment you had
• smoking – smokers are much more likely to develop acute leukaemia than non-smokers, and studies have shown that parents who smoke in the home may increase the risk of leukaemia in their children
• being very overweight (obese) – some studies have shown that people who are very overweight have a slightly higher risk of developing leukaemia than those who are a normal weight
• genetic disorders – a small number of cases of childhood acute lymphoblastic leukaemia are thought to be related to genetic disorders, including Down's syndrome
• having a weakened immune system – people with lowered immunity (as a result of having HIV or AIDS or taking immunosuppressants) have an increased risk of developing leukaemia

Environmental factors

Extensive research has been carried out to determine whether the following environmental factors could be a trigger for leukaemia:

• living near a nuclear power station
• living near a power line
• living near a building or facility that releases electro-magnetic radiation, such as a mobile phone mast

There's currently no firm evidence to suggest that any of these environmental factors increases the risk of developing leukaemia.

Cancer Research UK has more information about acute lymphoblastic leukaemia risks and causes.

Treating acute lymphoblastic leukaemia

As acute lymphoblastic leukaemia is an aggressive condition that develops rapidly, treatment usually begins a few days after diagnosis.

Treatment is usually carried out in the following stages: 

• induction – initially, treatment aims to kill the leukaemia cells in your bone marrow, restore the balance of cells in your blood and resolve any symptoms you may have
• consolidation – aims to kill any remaining leukaemia cells in your central nervous system
• maintenance – involves taking regular doses of chemotherapy tablets to prevent the leukaemia returning

Chemotherapy is the main treatment for acute lymphoblastic leukaemia. Other treatments you may need include antibiotics and blood transfusions. In some cases, a bone marrow transplant may also be needed to achieve a cure.

Read more about treating acute lymphoblastic leukaemia.

Complications of acute lymphoblastic leukaemia

If a cure for acute lymphoblastic leukaemia isn't possible, there's a risk that the lack of healthy blood cells can make the person:

• extremely vulnerable to life-threatening infections (because of the lack of white blood cells)
• prone to uncontrolled and serious bleeding (because of the lack of platelets)

These two complications, plus a number of others, are discussed further in complications of acute lymphoblastic leukaemia.

Outlook

The outlook for children with acute lymphoblastic leukaemia is usually good. Almost all children will achieve remission (a period of time where they're free from symptoms), and 85% will be completely cured.

The outlook for adults with acute lymphoblastic leukaemia is less promising. Around 40% of people aged between 25 and 64 will live for five years or more after receiving their diagnosis. In those aged 65 or over, around 15% will live for five years or more after being diagnosed.

Cancer Research UK has more detailed survival statistics for acute lymphoblastic leukaemia.

Help and support

If you or a family member has been diagnosed with acute lymphoblastic cancer, Leukaemia Care can provide further information, advice and support.

You can call their freephone helpline – 08088 010 444 – or email: support@leukaemiacare.org.uk

Cancer UK has more about all aspects of acute lymphoblastic leukaemia, and you can also read living with cancer for more information and advice about cancer in general.