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Despite being a rare disease, leukemia is the most common cancer in children and teens, accounting for almost one-third of childhood cancers.

Leukemia is cancer of the blood cells. The body produces three kinds of blood cells: red blood cells that carry oxygen throughout the body; white blood cells that fight infections; and blood platelets that are responsible for blood clotting.

Leukemia usually starts in white blood cells, causing an abundance of immature cells that crowd out the other normal white blood cells, red blood cells and platelets the body needs to be healthy. The immature or abnormal cells are not capable of performing their regular tasks, which leads to anemia, easy bruising or bleeding, fatigue, fever, increased infections, weight loss and other symptoms.

Leukemia can be either fast-growing (acute) or slow-growing (chronic). Childhood leukemia is almost always acute. There are two main types of acute leukemia:

  • Acute lymphocytic leukemia (ALL) accounts for three out of four childhood leukemias.
  • Acute myeloid leukemia (AML) accounts for most of the remaining cases. 

The slower-growing type of leukemia, chronic myeloid leukemia (CML), is rare in children.


Symptoms and Diagnosis

Since most leukemia in children is acute and fast-moving, symptoms such as fatigue, easy bruising, fever and loss of appetite should be addressed immediately. This type of cancer becomes worse quickly if it is not treated as it spreads through the bloodstream to vital organs including the brain.

Because leukemia doesn’t usually form tumors, tests that examine the blood and bone marrow are used to detect and diagnose this disease. A blood test examines the number of red and white blood cells and platelets, and the ratio of the types of blood cells, in the blood. A biopsy and microscopic examination of the bone marrow is another test for leukemia, as is an examination of fluid from the spinal column.

If a child is diagnosed with leukemia, other blood tests will be done to assess liver, kidney and other organ function. Tests may also be done to check for infections so they can be treated right away. Leukemia affects the body’s ability to fight infection and small infections can become worse rapidly.



Fifty years of dedicated research and development of new drugs and targeted therapies have made all the difference in improving the survival rate of childhood leukemia. In the 1960s, ALL was fatal for every child who was diagnosed. After new combinations of drugs were developed and aggressive treatment of the brain and spinal fluid were incorporated into treatment protocols, the five-year survival rate for children with ALL is now more than 85 percent. The development of new treatments for AML has seen similar success, ranging from 60 percent to 80 percent five-year survival rate depending on the subtype of AML and other factors.

Classifying the type (such as ALL or AML) and associated characteristics of leukemia cells is an important factor in treating the disease. While stages of other cancers are determined by the size of the cancerous tumor and spread to other organs, leukemia risk is measured not only by the extent to which it has spread to other organs such as the liver, spleen, lymph nodes or brain and spinal cord, but also on various genetic markers of the cancerous cells themselves.

The main treatment for leukemia is chemotherapy, the use of drugs to kill cancer cells. Sometimes bone marrow transplants, blood transfusions and radiation therapy are used as well. Chemotherapy is delivered into a vein and/or the spine and in pills. Children may receive several drugs at different times during the course of treatment depending on the type of leukemia and the extent to which the disease has spread. Treatment may last up to three years.

Chemotherapy kills fast-growing cells, such as cancer cells. However, chemotherapy also targets other fast-growing, healthy cells such as those in the lining of the mouth and intestines, hair and bone marrow. This can lead to side effects, including hair loss, mouth sores, loss of appetite, fatigue, diarrhea and nausea. The doctor can prescribe drugs to help manage some of the side effects such as nausea and vomiting, and these symptoms usually disappear after treatment ends.


Important questions to ask your child's doctor about Leukemia.