|Acute Myelogenous Leukemia
(AML, Acute Myeloid Leukemia, Acute Myeloblastic Leukemia, Acute Granulocytic Leukemia, Acute Nonlymphoblastic Leukemia)
Acute myelogenous leukemia (AML) is a cancer of the blood and bone marrow, in which the bone marrow makes abnormal myeloblasts (a type of white blood cell), red blood cells, or platelets. AML begins in immature myeloblasts and progresses very quickly. It may also be the end state of chronic myelogenous leukemia (CML). AML may occur in either children or adults.
Cancer occurs when cells in the body (in this case, myeloblasts) become abnormal, and divide without control or order. Leukemia is cancer of the white blood cells and their parent cells. Leukemia cells do not function normally and cannot do what normal blood cells do, such as fight infections. This means that the person is more likely to become infected with viruses or bacteria. Because the cancerous cells also overgrow the bone marrow, they can force out other normal components, such as the cells that make platelets. Platelets are necessary for proper blood clotting, and so, people with untreated leukemia may also have unexpected bleeding or may bruise easily.
The cause of AML is unknown, although smoking after age 60 doubles the risk of developing this condition.
The following factors increase your chances of developing AML:
- Sex: male
- Smoking, especially after age 60
- Previous chemotherapy or radiation therapy treatment
- Previous treatment for childhood acute lymphoblastic leukemia (ALL), Hodgkin’s disease, non-Hodgkin’s lymphoma, and certain other cancers
- Exposure to atomic bomb radiation or nuclear reactor accident
- Exposure to the chemical benzene
- History of a blood disorder, such as myelodysplastic syndrome (pre-cancerous changes in the white cells and precursor cells of the bone marrow)
The following risk factors are specific to childhood AML:
- Having a brother or sister with leukemia
- Race: Hispanic
- Exposure to cigarette smoke or alcohol before birth
- History of myelodysplastic syndrome or aplastic anemia
- Previous chemotherapy or radiation therapy treatment
- Exposure to ionizing radiation
- Exposure to chemicals such as benzene
- Certain genetic disorders, such as Down’s syndrome
- Shortness of breath
- Paleness (a sign of anemia)
- Easy bruising or bleeding
- Petechiae (flat, pinpoint spots under the skin caused by bleeding)
- Loss of appetite
- Weight loss
- Bone pain
- Joint pain
- Enlargement of the liver and spleen
- Swelling, pain, and bleeding of the gums
- Painless lumps in the neck, underarm, stomach, or groin
Note : These symptoms may also be caused by other, less serious health conditions. Anyone experiencing these symptoms should see a doctor.
Your doctor will ask about your symptoms and medical history, and perform a physical exam. He or she may also check for swelling of the liver; spleen; or lymph nodes in the armpits, groin, or neck. You will likely be referred to an oncologist, a doctor who specializes in treating cancer.
Tests may include the following:
- Blood tests – to check for changes in the number or appearance of different types of blood cells
- Bone marrow aspiration – removal of a sample of liquid bone marrow to test for cancer cells
- Bone marrow biopsy – removal of a sample of liquid bone marrow and a small piece of bone to test for cancer cells
- Spinal tap – removal of a small amount of cerebrospinal fluid to check for cancer cells
- Routine microscopic exam – examination of a sample of blood, bone marrow, lymph node tissue, or cerebrospinal fluid
- Bone, blood marrow, lymph node tissue, or cerebrospinal fluid tests – to distinguish between types of leukemia
- Cytogenetic analysis – a test to look for certain changes of the chromosomes (genetic material) of the lymphocytes.
- Immuophenotyping – a process by which the proteins on the surface of the cells and the antibodies the body produces in response are examined. This helps distinguish lymphoblastic from myeloid leukemia and may also be used to determine what types of therapy are most likely to be effective.
- Chest x-ray – x-rays of the chest that may detect signs of lung infection or cancer in the chest
- CT /
- scan – a type of x-ray that uses a computer to make pictures of structures inside the body
- MRI scan – a test that uses magnetic waves to make pictures of structures inside the body
- Gallium scan and bone scan – injection of a radioactive chemical into the bloodstream to detect areas of cancer or infection
- Ultrasound – a test that uses sound waves to examine masses and organs inside the body
Once AML is identified, it can be classified as one of eight subtypes, based on the type of cell from which leukemia developed. For instance, in the subtype referred to as M6, or erythroid leukemia, leukemia originated in red blood cells. Classification is important, because it can help doctors predict the an individual’s prognosis and design a treatment plan.
Talk with your doctor about the best treatment plan for you. Treatment of AML usually involves two phases: remission induction therapy (to kill leukemia cells) and maintenance therapy (to kill any remaining leukemia cells that could grow and cause a relapse). Treatment options include:
Chemotherapy is the use of drugs to kill cancer cells. It may be given in many forms, including pill, injection, and via a catheter. The drugs enter the bloodstream and travel through the body killing mostly cancer cells, but also some healthy cells.
For AML that has spread—or may spread—to the brain and spinal cord, intrathecal chemotherapy (chemotherapy drugs placed directly into the spinal column) may be used.
Radiation therapy involves the use of radiation to kill cancer cells and shrink tumors. For AML, external radiation therapy is used. In external radiation therapy radiation is directed at the tumor from a source outside the body. This type of treatment is used for AML that has spread—or may spread—to the brain and spinal cord. It can also be used to treat bone pain that comes from bone involvement by the leukemia.
Chemotherapy With Stem Cell Transplant
Chemotherapy is followed by a transplantation of stem cells (immature blood cells) to replace blood-forming cells destroyed by cancer treatment. Stem cells are removed from the blood or bone marrow of the patient or donor, and infused into the patient.
Other Drug Therapy
Other anticancer drugs, including arsenic trioxide and all-trans retinoic acid (ATRA), may be used in a subtype of AML called promyelocytic leukemia. These drugs can kill leukemia cells, stop them from dividing, or help them mature into white blood cells.
Biologic therapy, which is still being tested in clinical trials, is the use of medications or substances made by the body to increase or restore the body's natural defenses against cancer. This type of therapy is also called biological response modifier therapy.
Since many people who develop AML have no risk factors, there is no way to prevent AML in most people. But since 20% of AML cases are related to smoking tobacco, not smoking is the best known way to prevent AML.