What is leukaemia?

Leukaemia is a form of cancer affecting the white blood cells. Blood cells include white cells to fight infection, red cells to carry oxygen and platelets which help stop bruising and bleeding. Blood cells are made in the bone marrow and when mature they are released into the peripheral blood. However, in leukaemia, these early cells fail to mature and multiply in an uncontrolled way, spilling out into the circulation. They also crowd out normal cells in the bone marrow effectively preventing normal blood cell production. This causes the symptoms of leukaemia which are anaemia, reduced resistance to infection and abnormal bleeding. It can also cause bony pain. This process usually happens very quickly and symptoms develop rapidly over a few days or weeks. Rapid development of leukaemia symptoms is called ‘acute’ leukaemia. The type of leukaemia: ‘lymphoblastic’ or ‘myeloid’ depends on what type of abnormal cell is found on testing.

Without treatment acute leukaemia can cause death in a few weeks from bone marrow failure. Treatment takes from 9 months to 2-3 years to complete depending on the type of leukaemia

There are two main types of acute leukaemia in children -:

• Acute lymphoblastic leukaemia (ALL)
• Acute myeloblastic (myeloid) leukaemia (AML)

ALL is the most common leukaemia accounting for 80% of cases, the remaining 20% being AML. ALL is also the most common childhood cancer. Children with Down syndrome are more likely to develop leukaemia. Other genetic conditions associated with leukaemia include neurofibromatosis, Shwachman Syndrome, Bloom Syndrome and ataxic telangiectasia.

Survival rates

Survival rates have improved dramatically with modern treatment from a 5 year survival of less than 10% in the 1960s to more than 80% in the 1990s. In the induction period of treatment, the first 4 weeks, approximately 2% of children with ALL will die usually from infection and 2% will fail to go into remission and therefore have a poor prognosis. ALL is fatal without treatment. The treatment is intensive and toxic and lasts up to 3 years. The emotional strain on the child and their family is considerable.

What is the incidence of leukaemia?

Around one third of all childhood cancers are leukaemias. Of these, 80% are the Acute Lymphoblastic (ALL) type. ALL is more common in areas of Britain with higher socio-economic status than average. Acute Myeloid Leukaemia is much less common and chronic forms of myeloid leukaemia are very rare.

Note: - chronic myeloid leukaemia is not covered by this guidance.

Leukaemia is more common in boys than girls. There is a sharp peak in incidence at age 2-3 years. 400 to 500 children develop a type of leukaemia each year in the UK. More than half of these will be aged under 5 at the time of diagnosis.