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About acute lymphoblastic leukaemia (ALL)
Leukaemia is a cancer of the white blood cells. White blood cells help to fight infection.
There are two different types of white blood cell – lymphoid cells (also known as lymphocytes) and myeloid cells. Normally these cells, which are produced in the bone marrow, repair and reproduce themselves in an orderly and controlled way. In leukaemia, however, the process gets out of control and the cells continue to divide but do not mature.
Acute lymphoblastic leukaemia is an overproduction of immature lymphoid cells, called lymphoblasts or blast cells.
Immature lymphoid cells fill up the bone marrow and stop it making healthy blood cells. As these cells are immature, they cannot work properly. This puts the child at increased risk of infection. Symptoms of leukaemia in children such as bruising and anaemia are caused by the bone marrow’s inability to make enough healthy red blood cells and platelets.
There are several types of childhood acute lymphoblastic leukaemia. These are identified according to the type of lymphoid cell affected and the stage during its development at which it becomes leukaemic:
- The affected lymphocytes may be either precursor (>98%) or mature
- Precursor cell leukaemias may involve either of the two types of lymphocyte: B-cells (87%) or T-cells (13%)
- Precursor B-cell ALL is further divided into three categories: null-cell, common ALL and pre-B ALL
- Common ALL is the most common type of childhood ALL, accounting for up to 70% of cases.
Knowing the type of ALL is important as it helps doctors work out the best treatment.
Leukaemia is the most common childhood cancer, accounting for nearly a third of all cases (31% and 29% in boys and girls, respectively) in Great Britain. ALL accounts for around four-fifths (78%) of all leukaemias diagnosed in children in the UK.
There is a peak in incidence of acute lymphoblastic leukaemia in children aged two to three years; more than half of all children diagnosed with acute lymphoblastic leukaemia are under the age of five years.
Boys have a greater risk than girls of developing ALL, by a factor of 4:3. The reason for this difference between the sexes is not known. Boys also require a longer duration of treatment (see below).
Childhood leukaemia survival rate
The survival rate for children diagnosed with acute lymphoblastic leukaemia is of over 86%. Acute lymphoblastic leukaemia survival rate is highest in children diagnosed between one and four years of age.
Until the 1960s childhood leukaemia was incurable. Today, thanks to improvements in care and sustained investment in research, the outlook for young patients diagnosed with ALL has dramatically improvedBack to top