Childhood Leukemia

About 2,000 children each year are diagnosed with childhood leukemia. The condition is a type of cancer that starts in blood-forming tissue and results in the production of large numbers of blood cells. Some of the risk factors for leukemia in children include having a sibling with the cancer, undergoing chemotherapy, and having certain genetic disorders. Common symptoms include such things as looking pale, bleeding or bruising easily, fever, shortness of breath, and frequent infections.

 

What Is Childhood Leukemia?

Leukemia is cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream. Each year, about 29,000 adults and 2,000 children in the United States are diagnosed with leukemia.
 
The two types of leukemia that most commonly affect children are:
 
  • Acute lymphoblastic leukemia (ALL)
  • Acute myelogenous leukemia (AML).
 
In rare cases, chronic lymphocytic leukemia (CLL) and chronic myelogenous leukemia (CML) will occur in children.
 

How Common Is It?

Cancer in children and adolescents is rare. However, childhood acute lymphoblastic leukemia (ALL) is the most common cancer in children, representing 23 percent of cancer diagnoses among children who are younger than 15 years of age. ALL occurs in about one of every 29,000 children in the United States each year, and AML accounts for about 10,600 new cases of leukemia annually. Approximately 700 cases of AML occur in people under the age of 20 each year.
 

Understanding Blood Cells

Normally, the body produces bone marrow stem cells (immature cells) that develop into mature blood cells. The three types of mature blood cells are:
 
  • Red blood cells that carry oxygen and other materials to all tissues of the body
  • White blood cells that fight infection and disease
  • Platelets that help prevent bleeding by causing blood clots to form.
 

Childhood Leukemia and Cells

In childhood leukemia, the bone marrow produces abnormal white blood cells, which are leukemia cells. At first, leukemia cells function almost normally. However, in time, they may crowd out normal white blood cells, red blood cells, and platelets, which makes it hard for blood to do its work.
 

Types of Leukemia

The different types of leukemia are grouped by how quickly the disease develops and gets worse (chronic versus acute). The types of leukemia are also categorized by which blood cells are affected (lymphoid versus myeloid).
 
Based on the aggressiveness of the disease and the blood cells that are affected, there are four common types of leukemia:
 
 
Acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML) are the most common types of childhood leukemia. While a child may develop chronic lymphocytic leukemia (CLL) or chronic myeloid leukemia (CML), these types of leukemia are rarely seen in children.
 

Causes and Risk Factors

No one knows the exact causes of childhood leukemia. Doctors can seldom explain why one person will get childhood leukemia and another person will not. However, leukemia research has shown that people with certain risk factors are more likely than others to develop childhood leukemia. A risk factor is anything that increases a person's chances of developing a disease.
 
Childhood ALL risk factors include:
 
  • Having a brother or sister with leukemia
  • Being Caucasian or Hispanic
  • Living in the United States
  • Being exposed to x-rays before birth
  • Being exposed to radiation
  • Past treatment with chemotherapy or other drugs that weaken the immune system
  • Having certain genetic disorders, such as Down syndrome.
 
Childhood AML risk factors include:
 
  • Having a brother or sister, especially a twin, with leukemia
  • Being Hispanic
  • Being exposed to cigarette smoke or alcohol before birth
  • Having a history of myelodysplastic syndrome
  • Past treatment with chemotherapy or radiation therapy
  • Being exposed to ionizing radiation or chemicals such as benzene
  • Having certain genetic disorders, such as Down syndrome.
 

Symptoms of Childhood Leukemia

Like all blood cells, leukemia cells travel through the body. Depending on the number of abnormal cells and where these cells collect, children with leukemia may have a number of symptoms. Children with leukemia frequently have low amounts of healthy red blood cells and platelets. As a result, there are not enough red blood cells to carry oxygen through the body (anemia). People who have anemia may:
 
  • Look pale
  • Feel weak and tired
  • Bleed and bruise easily.
 
Other common symptoms of leukemia in children include:
 
  • Fever
  • Shortness of breath
  • Fatigue
  • Frequent infections
  • Painless blue or purple lumps in the neck, underarm, stomach, or groin
  • Pain or feeling of fullness below the ribs
  • Paleness or pallor
  • Headaches
  • Easy bleeding or bruising
  • Loss of appetite
  • Tiny red spots (called petechiae) under the skin
  • Bone or joint pain.
  • Painless blue green lumps called chloromas that appear around the eyes.
 

Screening Tests

There are no screening tests for childhood leukemia. Screening does not appear to be useful for cancers such as leukemia that appear throughout the body during their earliest stages. Instead, children with possible leukemia symptoms should see their physician, who can determine if further testing is needed.
 

Diagnosing Childhood Leukemia

If a child has symptoms that suggest childhood leukemia, the physician may first order blood tests. A sample of blood is examined to determine:
 
  • The number of normal blood cells
  • What the cells look like
  • If any leukemia cells are present in the blood.
 
For a definitive diagnosis of childhood leukemia, a doctor who specializes in leukemia will examine a sample of bone marrow under a microscope. The sample is obtained by a procedure called bone marrow aspiration. In this procedure, the doctor will insert a needle into a large bone, usually the hip, and remove a small amount of liquid bone marrow for examination.
 
If leukemia cells are found in the bone marrow sample, the patient's doctor will order other tests to find out the extent of the disease. For example, a spinal tap, which is also called a lumbar puncture, is used to check for leukemia cells in the cerebrospinal fluid, which is the fluid that fills the spaces in and around the brain and spinal cord.
 

Treatment Options

You can learn more about the specific childhood leukemia treatment options by going to the full eMedTV articles on Childhood ALL Treatment and Childhood AML Treatment.
 

Other Names for Childhood Leukemia

Acute myelogenous leukemia is also called:
 
  • AML
  • Acute myeloid leukemia
  • Acute myeloblastic leukemia
  • Acute granulocytic leukemia
  • Acute non-lymphocytic leukemia.
 
Other names for acute lymphocytic leukemia include:
 
  • ALL
  • Acute lymphoblastic leukemia
  • Acute lymphatic leukemia
  • Acute lymphocyte leukemia
  • Acute lymphoid leukemia. 
 

Summary

Key information about childhood leukemia includes the following:
 
  • Leukemia is a type of cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream. In childhood leukemia, the bone marrow produces abnormal white blood cells, which are leukemia cells.
 
 
  • In cancers such as leukemia that appear throughout the body during their earliest stages, screening does not appear to be useful. Instead, children with possible symptoms of leukemia should be seen by their physician.
 
  • Each year about 2,000 children are diagnosed with childhood leukemia.
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Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD