What is leukemia?
Leukemia is a type of cancer that starts in early forms of white blood cells. White blood cells are cells that typically fight infections. Early forms of white blood cells live in bone marrow, the spongy tissue inside most bones in the body. When early white blood cells become leukemia (or cancer cells), they grow out of control and crowd out the normal young blood cells in the bone marrow. From there, the cancerous cells spread through the blood to other parts of the body.
Leukemia is either fast growing (acute) or slower growing (chronic). Almost all leukemia in children is acute. From most common to most rare, the four types of pediatric leukemia are: Acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), chronic myelogenous leukemia (CML) and juvenile myelomonocytic leukemia (JMML). ALL affects white blood cells called lymphocytes, whereas AML affects white blood cells called myeloid cells.
How is leukemia diagnosed?
The first test usually performed to diagnose leukemia is a complete blood count (CBC) to determine how many types of each blood cell are in the blood. Children with leukemia often do not have normal numbers of red blood cells and platelets. Some children have too many white blood cells in the blood; some of these white blood cells will be in early forms (called blasts) which are normally only found in the bone marrow. Sometimes the leukemia cells (blasts) are not seen in the blood, and the number of normal white blood cells in the blood may be low.
If leukemia is suspected from the CBC, the doctor will perform a bone marrow aspiration and biopsy by using thin, hollow needles to remove small amounts of bone marrow (usually from the hip bone). Slides from the bone marrow sample are looked at under a microscope and the doctors can see whether or not leukemia cells are present. Other lab tests are sent from the marrow sample to help decide the types of leukemia and then a diagnosis can be made.
In ALL and AML, doctors can also look for leukemia cells in the cerebrospinal fluid (liquid that covers the brain and spinal cord) by performing a lumbar puncture, also known as a spinal tap.
Solid tumors are staged based on whether or not the cancer has spread to other parts of the body. This type of staging dose does not apply to leukemia, because it arises in the bone marrow and always spreads throughout the body via the blood. Because leukemia typically doesn’t form masses, imaging tests are not typically useful when diagnosing the disease. However, sometimes leukemia cells can clump together in different parts of the body to form a mass; in those cases, the doctor might get imaging tests.
Parents should understand the type and subtype of their child’s leukemia when reviewing treatment options.
When deciding on a cancer treatment plan, it is also important to weigh the chance of cure or improvement against the side effects of a particular treatment. Common treatments for childhood leukemia include chemotherapy, targeted therapy, high-dose chemotherapy and stem cell transplant, and radiation. The first course of action is usually a combination of chemotherapy drugs. For most cases of childhood leukemia, chemotherapy is the only type of treatment that children will receive. In some instances, higher doses of chemotherapy and/or radiation are used, which can destroy healthy cells in the bone marrow; in those instances, a stem cell transplant can restore the blood-forming stem cells of the bone marrow.
A promising type of immunotherapy patients with relapsed or refractory ALL, called CAR T-cell therapy, works by modifying the body’s T-cells — immune system cells that hunt and destroy abnormal cells, such as cancer cells. The patient’s own T-cells are collected, genetically engineered to target a protein that expresses leukemia cells, and then are intravenously introduced back into the body. Currently, this treatment is only available for some cases of ALL that have not responded to standard treatments.
Emotional support services
Even with an expert treatment team and support system, having a child diagnosed with cancer can be an overwhelming experience. Parents can learn strategies to reduce stress and anxiety by openly discussing their experiences with other parents of children with cancer.
The medical and psychosocial team members can also help parents anticipate expected reactions from their child depending on the child’s specific age and temperament, as well as inform families of possible emotional side effects from the medications, such as steroids.
Additionally, psychosocial clinicians and patient activities staff can help children learn to handle medical procedures and clinic visits. Providers and can map out the treatment course over time to help parents anticipate changes in their family routines to support siblings and foster life at home.
Learn more about pediatric leukemia from Dana-Farber/Boston Children’s Cancer and Blood Disorders Center.