The most common cancer in children is leukemia, accounting for one third of all childhood cancers. Most of these are the acute type, in contrast to the chronic type which is more common in adults.
Leukemia is cancer of the white blood cells (WBCs), although other blood cells may also be affected. There is proliferation of white blood cells that crowd out the other cells, particularly the red blood cells, resulting in a decrease in the normal function of blood in carrying oxygen and other nutrients. The disease starts in the bone marrow where blood cells are manufactured, and spreads to other parts of the body.
Nearly 75 percent of childhood leukemias are of the Acute Lymphocytic Leukemia (ALL) type. It affects very young children, peaking at 2-4 years of age. The rest of the leukemias are mostly of the non-lymphocytic type and occur in children and teenagers.
The use of chemotherapy has greatly improved the survival rate of children with leukemia. Whereas in the past almost all children with leukemia had a poor prognosis, chemotherapy has increased the 5 year survival rate of sick children. If after 5 years the sick child survives, he is most like to have been completely cured, because relapse is rarer after this period.
In spite of this, many factors affect the survival of children with leukemia, and complications of the disease and its treatment may play a negative role.
Complications of Leukemia in Children
The complications in the course of this blood disease are related to the nature of the malignancy itself and the effects of its therapy.
Leukemia and chemotherapy may bring about suppression of the immune system of children. Although there is a proliferation of white blood cells that are normally active during infections, the cells produced in leukemia are immature and do not function well during infections. Chemotherapy usually decreases the growth of both normal and abnormal cells, so the immune system is generally suppressed. Children are thus more susceptible to recurrent bacterial and fungal infections.
Other types of blood cells are crowded out by the WBCs, and those involved in normal blood clotting may be severely affected. This leads to the increased tendency for bleeding which may be seen as bruises or hematomas. However, the most dangerous bleeding may occur in the brain, resulting in intracranial hemorrhage. This may lead to an increase in intracranial pressure and death if uncontrolled.
On the other hand, abnormal thickening of the blood or sludging due to the white blood cell proliferation brings about thrombosis and increased coagulation. These can cause small infarcts in the brain and other parts of the body. This condition may progress to disseminated intravascular coagulation which can deteriorate to further bleeding tendencies.
Treatment with immunosuppressants like corticosteroids can bring about obesity, osteoporosis and growth suppression, which are long term side effects of these drugs. Other drugs may increase the risk for heart disease, hypertension and hypercholesterolemia.
Other neurologic complications may occur because of the involvement of the meninges (the membranes covering of the brain), treatment-related neurotoxicities and secondary malignancies. Mental and motor function of children may be adversely affected.
At present the survival rates of children with leukemia have quadrupled since half a century ago. Most patients under the age of 19 are expected to improve with the different drugs, bone marrow and stem cell transplants. However, death from leukemia remains to be the number one cause of mortality from cancer in young children.
American Cancer Society, “Childhood Leukemia” accessed 12/08/10
AJNR, “Childhood Leukemia: Central Nervous System Abnormalities during and after Treatment” accessed 12/08/10
Health Central, “Acute Lymphocytic Leukemia – Complications” accessed 12/08/10