Leukaemia is a cancer of the blood forming system, which is found in the bone marrow (the soft inner part of our bones). Most types of leukaemia cause abnormal white blood cells to be made in the bone marrow. These cells do not work normally and so do not give the protection from infection that they should. These abnormal white blood cells can get into the blood stream and circulate around the body. They can build up in the lymph nodes, bone marrow and spleen and cause swelling.  They can also affect the liver and the brain and spinal cord.

Depending on how fast it develops and gets worse, there are two main groups of leukaemia:

    •     Acute leukaemia
    •     Chronic leukaemia

There are two main types of acute leukaemia:

    •     Acute myeloblastic leukaemia (AML)  
    •     Acute lymphocytic leukaemia (ALL)

ALL is the main type of leukaemia affecting children.  More than 8 out of 10 cases of leukaemia in children are ALL and the peak age for diagnosis is 4 years old.  AML is the commonest type of leukaemia in adults.  The incidence in adulthood increases with age, with AML being most common in the over 65s.

The incidence of acute leukaemia is approximately 2000 new cases per year in France, of which acute myeloblastic leukaemia represents around half, that is to say 1000 new cases per year. Acute leukaemia (both lymphoblastic and myeloblastic) represents 30-35% of cancers in children. They are split into 80% acute lymphoblastic leukaemia and 20% acute myeloid leukaemia. In France, the incidence of acute leukaemia in children is estimated at 4.02 per 100,000 of population per year (approximately 600 new cases per year: 500 acute lymphoblastic leukaemia and 100 acute myeloid leukaemia).

Today, thanks to progress made in supportive care and well-defined chemotherapy protocols, the prognosis of acute lymphoblastic leukaemia has improved considerably. Meanwhile, because of the global seriousness of the illness, the prognosis for acute myeloid leukaemia remains limited. Currently, acute myeloid leukaemias are treated principally by chemotherapy with the objective of destroying the blast cells.

1. Parkin DM et al. L’incidence des cancers de l’enfant dans le monde. Pédiatrie 1989;44:725-736
2. UK Childhood Cancer Research Group, National Registry of Childhood Tumours. 2004.