Definition

Leukemia is a type of cancer that develops in the bone marrow. With acute myeloid leukemia (AML), the bone marrow makes abnormal myeloid cells that are precursors to blood cells, including:

• Myeloblasts—a stem cell that evolves into specific types of white blood cells that help the body fight infection
• Red blood cells (RBCs)—carry oxygen
• Platelets—a blood component involved in clotting blood

The leukemia cells do not function normally. The abnormal cells also overgrow the bone marrow, forcing normal cells out. Without normal cells, anemia, bleeding problems, and infections easily develop.

White Blood Cells Copyright © Nucleus Medical Media, Inc.

Causes

Cancer occurs when cells in the body divide without control or order. Normally, cells divide in a regulated manner. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms. The term cancer refers to malignant growth of cells or tissue. These growths can invade nearby tissues. Cancer that has invaded nearby tissues can then spread to the blood and other parts of the body.

It is not clear exactly what causes these problems in the cells, but it is probably a combination of genetics and environment.

Risk Factors

AML is more common in those of Hispanic descent. Other factors that may increase your child's chances of AML:

• Genetic factors:
  • Having a sibling, especially an identical twin, who develops leukemia
  • Having a genetic condition such as Down syndrome
• Exposure to radiation
• Exposure to certain chemicals such as benzene, a chemical used in the cleaning and manufacturing industries
• History of other blood disorders such as polycythemia vera, essential thrombocytosis, or myelodysplastic syndrome

Symptoms

AML may cause:

• Fever
• Frequent infections
• Shortness of breath
• Paleness
• Easy bruising or bleeding
• Flat, pinpoint spots under the skin caused by bleeding—petechiae
• Weakness, fatigue
• Loss of appetite, weight loss
• Bone and joint pain
• Painless lumps in the neck, underarms, stomach, or groin
• Bleeding gums

Diagnosis

The doctor will ask about your child’s symptoms and medical history. A physical exam will be done. The doctor will check for swelling of the liver, spleen, and lymph nodes.

Test to assess bodily tissues or other structures include:

• Blood tests
• Bone marrow biopsy or aspiration
• Lumbar puncture —tests the fluid that surrounds the brain and spinal cord for the presence of cancer
• Cytogenetic analysis—to look for DNA changes in the lymphocytes
• Immunophenotyping—examination of the proteins on cell surfaces and the antibodies produced by the body

Imaging tests are used to evaluate bodily structures. These may include:

• Ultrasound
• Chest x-ray
• CT scan
• MRI scan
• Gallium scan and bone scan

Once AML is identified, it can be classified. These subtypes are based on the type of cell from which leukemia developed. This is important because it can help the doctor make a prognosis and develop a treatment plan.

Bone Marrow Biopsy Copyright © Nucleus Medical Media, Inc.

Treatment

Talk with the doctor about the best plan for your child. Treatment of AML usually involves 2 phases:

• Remission induction therapy—to kill leukemia cells
• Consolidation—additional chemotherapy to kill any remaining leukemia cells that could grow and cause a relapse
• Maintenance therapy—not needed for children with AML

Treatment may include:

• Chemotherapy —usually with multiple medications given into a vein and the spinal column
• External radiation therapy —targets a certain part of the body
• Stem cell transplant —to replace the affected bone marrow with healthy bone marrow after complete destruction with treatment in children:
  • without complete remission
  • with intermediate-risk disease
  • with poor-risk disease or unable to tolerate chemotherapy
• Other drug therapy may be used to kill leukemia cells, stop them from dividing, or help them mature into white blood cells
• Biological therapy—involves using medications or substances made by the body to increase or restore the body’s natural defenses against cancer
• Antibiotics to treat and prevent infections
• Medications to treat anemia and treatment side effects, such as like nausea and vomiting

Prevention

There are no current guidelines to prevent AML because the cause is unknown.