A childhood leukemia diagnosis usually starts with a simple blood test. A doctor may order this blood test after evaluating the patient’s symptoms. Other times, the test is part of a routine doctor’s appointment.
If the test shows abnormal levels of red or white blood cells or the presence of leukemia cells, a bone marrow biopsy is ordered. This requires taking a sample of bone marrow from the hip with a needle, and then looking for the presence of disease.
A lumbar puncture may also be also performed to determine whether leukemia has affected the central nervous system. During this procedure, health care professionals use a needle to remove cerebrospinal fluid from the spine.
At the Children's Cancer Hospital, these procedures are performed under anesthesia for minimal discomfort to your child. Special doctors called hematopathologists use a full battery of laboratory tests to identify the specific leukemia type and subtype.
While many cancers are defined by their stages, there is no widely used staging system for childhood leukemia. Instead, patients are placed in risk groups depending on their condition and how far the disease has progressed. Doctors use these risk groups to help plan a patient's treatment.
(Source: National Cancer Institute)
Acute Lymphoblastic Leukemia (ALL)
Risk groups for childhood acute lymphoblastic leukemia are described as:
Standard (low) risk: Includes children aged 1 to 9 years who have a white blood cell count of less than 50,000/µL (or millionths of a liter) at diagnosis.
High risk: Includes children younger than 1 year or older than 9 years and children who have a white blood cell count of 50,000/µL or more at diagnosis.
Other factors that affect the risk group include the following:
- Whether the leukemia cells formed from B lymphocytes or T lymphocytes
- Whether there are certain changes in the chromosomes of the lymphocytes
- How quickly the leukemia responds to initial therapy
It is important to know the risk group in order to plan treatment. Children with high risk ALL usually receive more aggressive treatment than children with standard risk ALL.
Acute Myeloid Leukemia (AML)
Childhood AML is described as newly diagnosed, in remission, or recurrent.
Newly diagnosed childhood AML: The disease has not been treated except to relieve symptoms such as fever, bleeding, or pain, and one of the following is true:
- More than 20% of the cells in the bone marrow are blasts (leukemia cells), or
- Less than 20% of the cells in the bone marrow are blasts and there is a specific change in the chromosome
Childhood AML in remission: The disease has been treated and the following are true:
- The complete blood count is almost normal.
- Less than 5% of the cells in the bone marrow are blasts (leukemia cells).
- There are no signs or symptoms of leukemia in the brain, spinal cord or other parts of the body.
Recurrent childhood AML has recurred (come back) after it has been treated. The cancer may come back in the blood and bone marrow or in other parts of the body.