Nearly one-third of all children and teens with cancer are diagnosed with childhood leukemia, making this form of childhood cancer by far the most common. Childhood leukemia is a cancer of the blood. It begins in the bone marrow, the soft interior of the bones responsible for the development of new blood cells. Leukemia cells in the bone marrow replicate more quickly than healthy cells, and do not die at the proper time, and eventually begin to crowd out healthy cells. As this happens, the cancerous cells enter the blood stream and quickly move around the body. As the leukemia cells invade other organs, they begin to impact the ability of those organs to function normally.
There are two main types of acute childhood leukemia: ALL and AML:
- Acute lymphocytic (lymphoblastic) leukemia (ALL): ALL is the most common form of childhood leukemia, accounting for approximately 75% of leukemia diagnoses. ALL develops from immature lymphocytes, which when healthy grow into white blood cells responsible for fighting infections and bacteria. Most ALL cases involve B cells, the lymphocytes responsible for making the antibodies that the body uses to fight viruses; however, some cases of ALL originate in T cells, which are responsible for fighting infection themselves.
- Acute myelogenous leukemia (AML): Approximately 25% of childhood leukemia cases are AML, also known as acute myeloid leukemia, acute myelocytic leukemia, or acute non-lymphocytic leukemia. AML originates in myeloid cells that are responsible for developing non-lymphocytic white blood cells, red blood cells, and platelets.
Juvenile myelomonocytic leukemia (JMML) is a very rare type of childhood leukemia that is usually diagnosed in children under the age of 4. Like AML, it originates in myeloid cells, but develops much more slowly than AML (yet still grows more rapidly than chronic leukemia common in adults). Chronic (slow-growing) leukemias such as chronic myelogenous leukemia (CML) and chronic lymphocytic leukemia (CLL) are extremely rare in children.
Detection and Diagnosis of Childhood Leukemia
Children are usually diagnosed with childhood leukemia once it has entered the blood stream and spread to other parts of the body, leading to visible symptoms of illness as the leukemia cells prevent the normal functioning of various organs. The most common symptoms of childhood leukemia are fatigue, headaches, paleness, fever, and infection. Of course, these are similar to symptoms of many routine childhood ailments; however, your child’s pediatrician may recognize them as potential warning signs of leukemia if they persist, reoccur frequently, and/or gradually worsen over time despite treatment. Easy bruising and bleeding is also a potential symptom of leukemia.
Should your child’s pediatrician believe that leukemia may be the source of your child’s symptoms, he or she will recommend a blood test, which can indicate the potential presence of leukemia cells in the blood. The blood test will determine how many cells of each type (red blood cells, white blood cells, and platelets) are present in your child’s blood. An abnormally high level of white blood cells and a corresponding low level of red blood cells and platelets may indicate leukemia. A technician will also examine the blood sample under a microscope to look for abnormalities in the blood cells themselves.
Should this blood test indicate the potential presence of leukemia in your child’s blood stream, your child will be referred to an oncologist for full diagnostic testing. The first step in a leukemia diagnosis is a bone marrow aspiration and biopsy. This test is done to determine if leukemia cells are present in the bone marrow itself. Usually performed together, a bone marrow aspiration involves removing a small amount of bone marrow through a syringe inserted through the bone via a thin, hollow needle. Then, using a slightly larger needle, a small piece of the bone together with some marrow is removed. The biopsy involves examining the bone and the marrow samples under a microscope to detect the presence of leukemia cells.
If your child is diagnosed with leukemia, his or her oncology team will begin a series of additional tests and scans in order to classify and stage the leukemia. These tests will help the oncologists determine the appropriate method of treatment. These additional tests may include:
- Lumbar puncture (otherwise known as a spinal tap) in order to determine if there are leukemia cells in the cerebrospinal fluid
- Chest x-ray: to detect the potential for an enlarged thymus or lymph nodes, as well as to determine if there is any pneumonia and/or lung infection
- CT scan or MRI: to detect the presence of leukemia in other organs such as the lymph nodes, spleen, liver, brain, and/or spinal cord
- PET scan: may be helpful in determining the extent to which leukemia cells have spread throughout the body
About American Childhood Cancer Organization
American Childhood Cancer Organization (ACCO) is a non-profit charity dedicated to helping kids with cancer and their families navigate the difficult journey from cancer diagnosis through survivorship. Internationally, ACCO is the sole U.S. member of Childhood Cancer International (CCI), the largest patient-support organization for childhood cancer in the world. Here in the United States, ACCO promotes the critical importance of ensuring continued funding into new and better treatment protocols for childhood cancer. And most importantly, ACCO is focused on the children: developing and providing educational tools for children fighting cancer and their families, empowering them in their understanding of childhood cancer and the medical decisions they must make during this difficult journey. All of ACCO’s resources are available free of charge for families coping with childhood cancer.
For additional information about childhood cancer or on ACCO, or to order resources for you or your child, please visit our website at www.acco.org.