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Acute myelogenous leukemia (AML) is a cancer of the blood and bone marrow — the spongy tissue inside bones where blood cells are made.
The word "acute" in acute myelogenous leukemia denotes the disease's rapid progression. It's called myelogenous (my-uh-LOHJ-uh-nus) leukemia because it affects a group of white blood cells called the myeloid cells, which normally develop into the various types of mature blood cells, such as red blood cells, white blood cells and platelets.
Acute myelogenous leukemia is also known as acute myeloid leukemia, acute myeloblastic leukemia, acute granulocytic leukemia and acute nonlymphocytic leukemia.
Symptoms
General signs and symptoms of the early stages of acute myelogenous leukemia may mimic those of the flu or other common diseases. Signs and symptoms may vary based on the type of blood cell affected.
Signs and symptoms of acute myelogenous leukemia include:
- • Fever
- • Bone pain
- • Lethargy and fatigue
- • Shortness of breath
- • Pale skin
- • Frequent infections
- • Easy bruising
- • Unusual bleeding, such as frequent nosebleeds and bleeding from the gums
When to see a doctor
Make an appointment with a doctor if you develop any signs or symptoms that seem unusual or that worry you.
Causes
Acute myelogenous leukemia is caused by damage to the DNA of developing cells in your bone marrow. When this happens, blood cell production goes wrong. The bone marrow produces immature cells that develop into leukemic white blood cells called myeloblasts. These abnormal cells are unable to function properly, and they can build up and crowd out healthy cells.
In most cases, it's not clear what causes the DNA mutations that lead to leukemia. Radiation, exposure to certain chemicals and some chemotherapy drugs are known risk factors for acute myelogenous leukemia.
Risk factors
Factors that may increase your risk of acute myelogenous leukemia include:
- Increasing age. The risk of acute myelogenous leukemia increases with age. Acute myelogenous leukemia is most common in adults age 65 and older.
- Your sex. Men are more likely to develop acute myelogenous leukemia than are women.
- Previous cancer treatment. People who've had certain types of chemotherapy and radiation therapy may have a greater risk of developing AML.
- Exposure to radiation. People exposed to very high levels of radiation, such as survivors of a nuclear reactor accident, have an increased risk of developing AML.
- Dangerous chemical exposure. Exposure to certain chemicals, such as benzene, is linked to a greater risk of AML.
- Smoking. AML is linked to cigarette smoke, which contains benzene and other known cancer-causing chemicals.
- Other blood disorders. People who've had another blood disorder, such as myelodysplasia, myelofibrosis, polycythemia vera or thrombocythemia, are at greater risk of developing AML.
- Genetic disorders. Certain genetic disorders, such as Down syndrome, are associated with an increased risk of AML.
Many people with AML have no known risk factors, and many people who have risk factors never develop the cancer.
Diagnosis
If you have signs or symptoms of acute myelogenous leukemia, your doctor may recommend that you undergo diagnostic tests, including:
- Blood tests. Most people with acute myelogenous leukemia have too many white blood cells, not enough red blood cells and not enough platelets. The presence of blast cells — immature cells normally found in bone marrow but not circulating in the blood — is another indicator of acute myelogenous leukemia.
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Bone marrow test. A blood test can suggest leukemia, but it usually takes a bone marrow test to confirm the diagnosis.
During a bone marrow biopsy, a needle is used to remove a sample of your bone marrow. Usually, the sample is taken from your hipbone (posterior iliac crest). The sample is sent to a laboratory for testing.
- Lumbar puncture (spinal tap). In some cases, it may be necessary to remove some of the fluid around your spinal cord to check for leukemia cells. Your doctor can collect this fluid by inserting a small needle into the spinal canal in your lower back.
- Genomic testing. Laboratory tests of your leukemia cells can identify specific genes, chromosome changes, and other issues unique to your leukemia, as well as to find genetic changes or mutations. This can help determine your prognosis and guide your treatment.
If your doctor suspects leukemia, you may be referred to a doctor who specializes in blood cancer (hematologist or medical oncologist).
Determining your AML subtype
If your doctor determines that you have AML, you may need further tests to determine the extent of the cancer and classify it into a more specific AML subtype.
Your AML subtype is based on how your cells appear when examined under a microscope. Special laboratory testing also may be used to identify the specific characteristics of your cells.
Your AML subtype helps determine which treatments may be best for you. Doctors are studying how different types of cancer treatment affect people with different AML subtypes.
Treatment
Treatment of acute myelogenous leukemia depends on several factors, including the subtype of the disease, your age, your overall health and your preferences.
In general, treatment falls into two phases:
- Remission induction therapy. The purpose of the first phase of treatment is to kill the leukemia cells in your blood and bone marrow. However, remission induction usually doesn't wipe out all of the leukemia cells, so you need further treatment to prevent the disease from returning.
- Consolidation therapy. Also called post-remission therapy, maintenance therapy or intensification, this phase of treatment is aimed at destroying the remaining leukemia cells. It's considered crucial to decreasing the risk of relapse.
Therapies used in these phases include:
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Chemotherapy. Chemotherapy is the major form of remission induction therapy, though it can also be used for consolidation therapy. Chemotherapy uses chemicals to kill cancer cells in your body.
People with AML generally stay in the hospital during chemotherapy treatments because the drugs destroy many normal blood cells in the process of killing leukemia cells. If the first cycle of chemotherapy doesn't cause remission, it can be repeated.
- Targeted therapy. Targeted therapy uses drugs that attack specific vulnerabilities within your cancer cells. The drug midostaurin (Rydapt) stops the action of an enzyme within the leukemia cells and causes the cells to die. Midostaurin is only useful for people whose cancer cells have the FLT3 mutation. This drug is administered in pill form.
- Other drug therapy. Arsenic trioxide (Trisenox) and all-trans retinoic acid (ATRA) are anti-cancer drugs that can be used alone or in combination with chemotherapy for remission induction of a certain subtype of AML called promyelocytic leukemia. These drugs cause leukemia cells with a specific gene mutation to mature and die, or to stop dividing.
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Bone marrow transplant. A bone marrow transplant, also called a stem cell transplant, may be used for consolidation therapy. A bone marrow transplant helps re-establish healthy stem cells by replacing unhealthy bone marrow with leukemia-free stem cells that will regenerate healthy bone marrow.
Prior to a bone marrow transplant, you receive very high doses of chemotherapy or radiation therapy to destroy your leukemia-producing bone marrow. Then you receive infusions of stem cells from a compatible donor (allogeneic transplant).
You can also receive your own stem cells (autologous transplant) if you were previously in remission and had your healthy stem cells removed and stored for a future transplant.
- Clinical trials. Some people with leukemia choose to enroll in clinical trials to try experimental treatments or new combinations of known therapies.