Acute Myeloid Leukemia (AML)

What Is Leukemia?

Leukemia is a type of blood cancer that affects the body's white blood cells (WBCs).

Normally, WBCs help fight infection and protect the body against disease. But in leukemia, white blood cells turn cancerous and don't work as they should. As more cancerous cells form in the blood and bone marrow (spongy tissue inside the bones), there's less room for healthy cells.

What Is Acute Myeloid Leukemia?

Acute myeloid leukemia (AML) happens when the body makes too many immature white blood cells. These cells, called myeloid blasts, can't mature into normal white blood cells.

Because AML develops and gets worse quickly, prompt treatment is very important.

Of kids who have leukemia, 20% have AML. Thanks to advances in therapy and clinical trials, the outlook for kids with AML has improved. With treatment, most are cured.

What Causes Acute Myeloid Leukemia?

The cause of acute myeloid leukemia is unknown. Some medical conditions can increase a child's risk of getting it. But just having a risk factor doesn't mean that a child will get AML.

Who Gets Acute Myeloid Leukemia?

Risks factors for kids include:

• having an identical twin who had leukemia before age 6
• being a fraternal twin or other sibling of a child with leukemia
• having an inherited genetic problems such as Li Fraumeni syndrome, Down syndrome, or Fanconi anemia
• having a non-inherited conditions such as myelodysplasia syndrome (a kind of pre-leukemia that stops blood cells from growing normally)
• having a condition called aplastic anemia (when the bone marrow doesn't make enough blood cells)
• prior radiation therapy or chemotherapy

What Are the Signs & Symptoms of Acute Myeloid Leukemia?

Acute myeloid leukemia develops quickly, and the cancerous cells multiply fast. That's why AML tends to get worse quickly if it's not treated.

The symptoms of all types of leukemia are generally the same and include:

• being very tired and weak
• swollen gums
• swollen lymph glands (or nodes)
• infections (like bronchitis or tonsillitis) that keep coming back
• a fever
• night sweats
• easy bruising or petechiae (tiny red spots on the skin caused by easy bleeding)
• bone and joint pain
• belly pain (caused by the build-up of cells in organs like the kidneys, liver, and spleen)

How Is Acute Myeloid Leukemia Diagnosed?

If a doctor suspects leukemia, a child may have these tests:

• Blood tests. Tests such as a complete blood count, liver function and kidney function panels, and blood chemistries can give important information about the number of normal blood cells in the body and how well the organs are working. The shapes and sizes of the blood cells are checked with a microscope.
• Imaging studies. These may include an X-ray, CT scan, MRI, or ultrasound. These studies can see whether there's a mass of leukemia cells in the chest that could affect breathing or blood circulation. They also can help doctors rule out other possible causes of a child's symptoms.
• Bone marrow aspiration and biopsy. In this procedure, the doctor inserts a needle into a large bone, usually the hip, and removes a small amount of bone marrow. The lab does these tests on the bone marrow sample:
  • Flow cytometry tests. Doctors carefully look at the cancer cells and figure out the type and subtype of the leukemia. This is important because treatment varies among different types of leukemia.
  • Genetic tests. By looking carefully at the blood or bone marrow, doctors check for changes in the genes. This can help doctors figure out the best treatment.
• Lumbar puncture (spinal (tap). Doctors use a hollow needle to remove a sample of cerebrospinal fluid (the fluid surrounding the brain and spinal cord) for exam in a lab.

How Is Acute Myeloid Leukemia Treated?

Chemotherapy

Doctors usually treat children who have acute myeloid leukemia with chemotherapy. These special drugs kill cancer cells. Which drugs a child gets and in what combination depends on the subtype of AML and and whether the cancer cells have mutations (genetic changes). How the cancer responds to the initial treatment is also important in choosing the type of chemo.

Doctors can give chemo:

• through a vein
• as an injection into a muscle
• by mouth in pill form
• with a spinal tap right into the cerebrospinal fluid, where cancerous WBCs can collect

The treatment goal is remission, which is when tests don't find any cancer cells in the body. Then, maintenance chemotherapy is used to keep the child in remission and prevent the cancer from coming back. The child will get maintenance chemo for 2 to 3 years.

Stem Cell Transplants

Kids who have an aggressive type of AML might need a stem cell transplant. Also called a bone marrow transplant, this involves:

• destroying cancer cells, normal bone marrow, and immune system cells with high-dose chemotherapy and/or radiation
• putting healthy donor stem cells back into the body
• rebuilding a healthy blood supply and immune system with the new stem cells 

Clinical Trials

Clinical trials are research studies that offer promising new treatments not yet available to the public. Doctors will decide if a child is a good candidate for a clinical trial.

Looking Ahead

Learning that a child has cancer is upsetting, and cancer treatment can be stressful for any family.

But remember, you're not alone. To find support, talk to your doctor or a hospital social worker. Many resources are available to help you get through this difficult time.