Adult acute myeloid leukemia (AML) is a type of cancer in which the bone marrow makes abnormal myeloblasts (a type of white blood cell), red blood cells, or platelets.

Adult acute myeloid leukemia (AML) is a cancer of the blood and bone marrow. This type of cancer usually gets worse quickly if it is not treated. It is the most common type of acute leukemia in adults. AML is also called acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia, and acute nonlymphocytic leukemia.

Normally, the bone marrow produces stem cells (immature cells) that develop into mature blood cells. There are 3 types of mature blood cells:

• Red blood cells that carry oxygen and other materials to all tissues of the body.
• White blood cells that fight infection and disease.
• Platelets that help prevent bleeding by causing blood clots to form.

In AML, the stem cells usually develop into a type of white blood cell called myeloblasts (or myeloid blasts). The myeloblasts in AML are abnormal and do not mature into healthy white blood cells. Sometimes in AML, too many stem cells develop into abnormal red blood cells or platelets. These abnormal white blood cells, red blood cells, or platelets are also called leukemia cells or blasts. Leukemia cells are unable to do their usual work and can build up in the bone marrow and blood so there is less room for healthy white blood cells, red blood cells, and platelets. When this happens, infection, anemia, or easy bleeding may occur. The leukemia cells can spread outside the blood to other parts of the body, including the central nervous system (brain and spinal cord), skin, and gums.

There are different subtypes of AML. The AML subtypes are based on how mature (developed) the cancer cells are at the time of diagnosis and how different they are from normal cells.

Smoking, previous chemotherapy treatment, and exposure to radiation may affect the risk of developing adult AML.

Possible risk factors for AML include the following:

• Being male.
• Smoking, especially after 60 years of age.
• Having had treatment with chemotherapy or radiation therapy in the past.
• Having had treatment for childhood acute lymphoblastic leukemia (ALL) in the past.
• Being exposed to atomic bomb radiation or the chemical benzene.
• Having a history of a blood disorder such as myelodysplastic syndrome.

Possible signs of adult AML include fever, feeling tired, and easy bruising or bleeding. The early signs of AML may be like those caused by the flu or other common diseases. A doctor should be consulted if any of the following problems occur:

• Fever.
• Shortness of breath.
• Easy bruising or bleeding.
• Petechiae (flat, pinpoint spots under the skin caused by bleeding).
• Weakness or feeling tired.
• Loss of appetite or weight loss.

Tests that examine the blood and bone marrow are used to detect (find) and diagnose adult AML.

The following tests and procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
• Complete blood count: A procedure in which a sample of blood is drawn and checked for the following:
• The number of red blood cells, white blood cells, and platelets.
• The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
• The portion of the sample made up of red blood cells.
• Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that produces it.
• Peripheral blood smear: A procedure in which a sample of blood is checked for the presence of blast cells, number and kinds of white blood cells, the number of platelets, and changes in the shape of blood cells.
• Bone marrow biopsy and aspiration: The removal of a small piece of bone and bone marrow by inserting a needle into the hipbone or breastbone. A pathologist views the bone and bone marrow samples under a microscope to look for abnormal cells.
• Cytogenetic analysis: A test in which the cells in a sample of blood or bone marrow are looked at under a microscope to find out if there are certain changes in the structure or number of chromosomes in the cells.
• Immunophenotyping: A process used to identify cells, based on the types of antigens or markers on the surface of the cell. This process is used to diagnose the subtype of AML by comparing the cancer cells to normal cells of the immune system.

Certain factors affect prognosis (chance of recovery) and treatment options. The prognosis (chance of recovery) and treatment options depend on:

• The age of the patient.
• The subtype of AML.
• Whether the patient received chemotherapy in the past to treat a different cancer.
• Whether there is a history of a blood disorder such as myelodysplastic syndrome.
• Whether the cancer has spread to the central nervous system.
• Whether the cancer has been treated before or recurred (come back).

It is important that acute leukemia be treated right away.