Childhood leukaemia

• What is Childhood Leukaemia
• Statistics on Childhood Leukaemia
• Risk Factors for Childhood Leukaemia
• Progression of Childhood Leukaemia
• Symptoms of Childhood Leukaemia
• Clinical Examination of Childhood Leukaemia
• How is Childhood Leukaemia Diagnosed?
• Prognosis of Childhood Leukaemia
• How is Childhood Leukaemia Treated?
• Childhood Leukaemia References

What is Childhood Leukaemia

Childhood leukaemias arise from cells located in the bone marrow. The bone marrow is the soft, spongy tissue located in the centre of most long bones and is responsible for the production of the cellular components of blood; namely white cells, red cells and platelets.
Lymphoblasts and myeloblasts are found in the bone marrow and are normal precursor cells of white and red blood cells. These lymphoblasts are influenced by many endogenous factors such as proteins and cytokines to differentiate into mature white and red blood cells.
Leukaemia occurs when there is abnormal proliferation of lymphoblasts and myeloblasts in the bone marrow.
It may secondarily affect the blood, lymph nodes, liver, spleen, bones, joints, central nervous system, testes and skin.

Statistics on Childhood Leukaemia

In children, 80% of leukaemias are Acute Lymphoblastic Leukaemia (ALL), 20% are Acute Myeloid Leukaemia (AML) and 1% are Chronic Myeloid Leukaemia (CML).
Leukaemia makes up approximately 35% of childhood malignancies and is the most common form of cancer in children. It is more common in males, caucasians and in the 2-5 year age group.

Risk Factors for Childhood Leukaemia

Childhood leukaemia results from abnormal gene function, commonly the result of mutations or inactivation of tumour suppressor genes (e.g. RB1, p53 ) or the activation of proto-oncogenes (e.g. MYC, ABL).
There is strong suggestion that inherited predisposition is a very important factor. Siblings of affected individuals can have up to a 4 four fold increase in risk. Twin studies have also established a genetic link.
Although irradiation, chemical carcinogens and oncogenetic viruses have been shown to induce leukaemia in animal models, the exact cause in children remains unknown and is probably multifactorial.
There is an increased incidence of leukaemia in children with Down syndrome and in children with some rare genetic diseases such as ataxia telangiectasia, Wiskott-Aldrich syndrome and Fanconi anaemia

Progression of Childhood Leukaemia

Childhood leukaemias usually present with widespread involvement of the bone marrow which may accompanied by the presence of large numbers of tumour cells in the peripheral blood. It may spread haematologically.

How is Childhood Leukaemia Diagnosed?

White cell count may be elevated, normal or depressed. Blast cells are usually present. Low haemoglobin may also be evident and the platelet count is usually low

Prognosis of Childhood Leukaemia

Prognosis differs according to each form of leukaemia. Intensive therapy results in an 70-80% remission rate of ALL, 60-70% for AML and 40-50% for juvenile CML. These rates are highly variable according to natural history.

How is Childhood Leukaemia Treated?

Treatment is specific for each type of childhood leukaemia. This usually involves chemotherapy carried out in different stages. Chemotherapeutic principles often employ many drugs into the regime; each directed at a certain aspect of the disease.
Later options may include bone marrow transplantation (according to suitability) from other donors or other unaffected bone marrow sites that may be within the patients body
In adjunct to this, blood products and antibiotics may also be administered respectively to try and normalise abnormal blood component levels and reduce the risk of infection.

Childhood Leukaemia References

[1] Cotran RS, Kumar V, Collins T. Robbins Pathological Basis of Disease Sixth Ed. WB Saunders Company 1999.
[2] Kumar P, Clark M. Clinical Medicine. Fourth Ed. WB Saunders, 1998.
[3] Robinson MJ, Roberton DM. Practical Paediatrics. 5th Edition. Churchill Livingstone. 2003.