Acute Myelocytic Leukemia

Definition

Definition of Acute Myelocytic Leukemia
Acute myelocytic leukemia is a life-threatening disease in which the cells that normally develop into neutrophils, basophils, eosinophils, and monocytes become cancerous and rapidly replace normal cells in the bone marrow.

• People may be tired or pale, easily susceptible to infection and fever, and bruise or bleed easily.
• Blood tests and bone marrow examination are needed for diagnosis.
• Treatment includes chemotherapy to achieve remission plus additional chemotherapy to avoid relapse.

Symptoms

Symptoms of Acute Myelocytic Leukemia
The first symptoms of AML are very similar to those of acute lymphocytic leukemia (see Leukemias: Acute Lymphocytic Leukemia (ALL)). Although meningitis occurs less often than in acute lymphocytic leukemia, AML cells can cause inflammation of the layers of tissue covering the brain and spinal cord (meninges).

Causes

Causes of Acute Myelocytic Leukemia
AML is neither contagious nor inherited. However, people who suffer from certain genetic disorders, such as Fanconi anemia, Klinefelter syndrome, Patau syndrome, Bloom syndrome, and Down syndrome, are at greater risk of developing AML than the general population. A child with Down syndrome is roughly 14 times as likely as the average child to develop leukemia.

Diagnosis

Diagnosis of Acute Myelocytic Leukemia
The diagnosis of AML is also similar to that of acute lymphocytic leukemia. A bone marrow biopsy (see Symptoms and Diagnosis of Blood Disorders: Bone Marrow Examination) is almost always done to confirm the diagnosis and to distinguish AML from other types of leukemia.

Treatment

Treatment of Acute Myelocytic Leukemia
Treatment is aimed at bringing about prompt remission—the destruction of all leukemia cells. However, AML responds to fewer drugs than does acute lymphocytic leukemia. In addition, treatment often makes people sicker before they get better, because the treatment suppresses bone marrow activity, resulting in fewer white blood cells, particularly neutrophils. Having too few neutrophils makes infection likely. Meticulous care is taken to prevent infections, and any that occur are promptly treated. Red blood cell and platelet transfusions are invariably also needed.

The first course of drug treatment (induction chemotherapy) generally includes cytarabine for 7 days by a continuous infusion and daunorubicin (or idarubicin or mitoxantrone) for 3 days.

Prognosis

Prognosis of Acute Myelocytic Leukemia
Without treatment, most people with AML die within a few weeks to months of the diagnosis. With therapy, between 20% and 40% of people survive at least 5 years, without any relapse. Because relapses almost always occur within the first 5 years after initial treatment, most people who remain leukemia-free after 5 years are considered cured. People who have the poorest prognosis are those older than 60, those who develop AML after undergoing chemotherapy and radiation therapy for other cancers, and those whose leukemia evolved slowly after a period of months to years of abnormal blood counts.

Prevention

Prevention of Acute Myelocytic Leukemia
High doses of radiation and exposure to the chemical benzene (used in the manufacture of plastics, rubber, and medicines) are strong risk factors. With the exception of people with such rare genetic conditions as Fanconi anemia, Klinefelter syndrome, Patau syndrome, Bloom syndrome, and Down syndrome, there is no known genetic predisposition to AML.