Leukemia is a type of cancer that affects your blood cells. Acute myelogenous leukemia is a specific type of leukemia. It’s also known as:
- acute myeloid leukemia
- acute non-lymphocytic leukemia
- acute myelocytic leukemia
- acute granulocytic leukemia
This article will take a closer look at acute myelogenous leukemia, including the risk factors, symptoms, and how it’s diagnosed and treated.
Acute myelogenous leukemia (AML) is a cancer of your blood cells. Its name tells you a little about the condition.
There are two kinds of leukemia: acute and chronic.
There are also two classes of blood cells: myeloid cells and lymphoid cells. Myeloid cells include red blood cells (RBCs), non-lymphocyte white blood cells (WBCs), and platelets. Lymphoid cells are white blood cells called lymphocytes.
AML is an aggressive cancer involving myeloid cells.
Some facts about acute myelogenous leukemia
- The National Cancer Institute estimates that 20,240 people will be diagnosed with AML in the United States in 2021.
- The most common leukemia in adults (age 20 years or older) is chronic lymphocytic leukemia (38%). AML is the second most common leukemia (31%).
- Although it is a common type of leukemia, AML only accounts for about 1 percent of all new cancers.
Your blood cells are made in your bone marrow. They begin as stem cells, then they turn into immature precursor cells called “blasts” before developing into mature blood cells. Once they’re fully developed, they move into your bloodstream and circulate throughout your body.
AML can develop when the DNA of an immature myeloid cell in your bone marrow changes, or mutates. The altered DNA instructs the cell to rapidly make copies of itself instead of becoming a mature blood cell.
The copies have the same damaged DNA, so they go on to make even more copies of the cell. This is called clonal expansion because all the cells are clones of the original damaged cell.
As the cells multiply, they fill your bone marrow and overflow into your bloodstream. Usually, the involved myeloid cell is a non-lymphocytic WBC, but once in a while, it’s an RBC or early platelet cell, known as a megakaryocyte.
Most of the cells are copies of the damaged immature cell, so they don’t function like mature cells do.
Each type of blood cell has a specific function:
- White blood cells fight infection in your body.
- Red blood cells carry oxygen to your organs and carbon dioxide to your lungs.
- Platelets help your blood clot, so you stop bleeding.
When your bone marrow is full of leukemia cells, it can’t make the necessary amount of the other blood cells.
Having low levels of these cells leads to most of the symptoms of AML. When the level of all blood cell types is low, it’s called pancytopenia.
Decreased RBC counts leads to anemia, which can cause:
Low numbers of functioning WBCs, known as leukopenia, can lead to:
- frequent infections
- unusual or uncommon infections
- infections that last a long time or keep coming back
Low platelet numbers, known as thrombocytopenia, can cause symptoms such as:
- bleeding gums
- heavy bleeding that’s difficult to stop
- easy bruising
- small red spots on your skin due to bleeding, or petechia
Blasts are larger than mature cells. When there are a lot of blasts in your bloodstream, as is the case with AML, they can get stuck in blood vessels and slow or stop blood flow. This is called leukostasis, and it’s a medical emergency that can cause stroke-like symptoms such as:
Blasts can also get stuck in your joints and organs, leading to:
There are certain factors that may increase your risk of AML. These risk factors include:
- smoking, especially if you’re over 60 years of age
- exposure to cigarette smoke in the womb and after birth
- previous cancer treatment with chemotherapy or radiation
- exposure to chemicals used in oil refining or rubber manufacturing such as benzene
- having a childhood blood cancer called acute lymphocytic leukemia
- having a previous blood disorder such as myelodysplastic syndromes
- being of the male gender increases the risk slightly
Your risk increases with age. On average, AML is initially diagnosed around the age of 68. It’s uncommon to be diagnosed before the age of 45.
Cumulative radiation from dental and other X-rays throughout your life is usually not enough to cause AML.
First, your doctor will do a complete medical history and physical exam to evaluate your overall health.
Next, your doctor will order blood and bone marrow tests. These tests can help diagnose AML. Typically, if you have AML, these tests will show a very large number of blasts and too few RBCs and platelets.
The types of blood tests that can help diagnose AML include:
- Complete blood count (CBC) with differential. A CBC gives you the number of each type of blood cell in your bloodstream and the percentage of each type of WBC.
- Peripheral blood smear. A blood sample is smeared on a slide and examined under a microscope. The number of each type of blood cell, including blasts, is counted. This test will also look for changes in cell appearance.
- Bone marrow biopsy. Bone marrow is removed from the center of one of your bones, usually the back of your pelvic bone, and examined under a microscope to determine the number of each type of blood cell, including blasts.
Some tests can identify leukemia cells under a microscope. This includes:
- Immunophenotyping. This uses antibodies that attach to specific antigens on different types of leukemia cells.
- Cytochemistry. This involves stains that identify different leukemia cells.
- Flow cytometry. This involves looking at identifying markers on the outside of cells, which can differentiate them from normal cells.
Other tests can identify chromosome and genetic abnormalities, such as:
- Cytogenetics. This approach involves identifying chromosome changes under a microscope.
- Fluorescence in situ hybridization (FISH). FISH identifies some changes that can be seen under a microscope and some that are too small to be seen.
- Polymerase chain reaction. This method identifies changes too small to see under a microscope.
The goal of AML treatment is complete remission. Around two-thirds of those with previously untreated AML achieve complete remission. Of these, about half live 3 years or more in remission.
Initial treatment of AML has two phases. Different chemotherapy protocols are used in both stages based on the AML subtype.
For untreated AML
To induce remission, chemotherapy is used to kill as many leukemia cells in the blood and bone marrow as possible. The goal is to achieve complete remission.
For AML in remission
The goal is to destroy any remaining leukemia cells and “consolidate” remission. Consolidation may be followed by a bone marrow transplant.
For AML that returns after achieving remission
There’s no standard treatment for recurrent AML or situations where remission is never achieved. Options include:
- combination chemotherapy
- targeted therapy with monoclonal antibodies
- stem cell transplant
- participation in clinical trials using new medications
No matter which stage you’re in, you may need supportive treatment when you receive chemotherapy. Supportive treatment may include:
- Prophylactic antibiotics and antifungals. These medications help you avoid infection when your WBC level is very low (neutropenic) making you vulnerable to infection.
- Immediate broad-spectrum antibiotics. These antibiotics may be used if you are neutropenic and develop a fever.
- Transfusion of RBC or platelets. This may be performed to prevent symptoms if you develop anemia or low platelets.
The 5-year survival rate is an estimate of how many people with cancer will be alive 5 years after diagnosis. It’s based on information from a large number of people with a specific cancer over many years.
This means it’s only a guide, not an absolute prediction of how long you or anyone else will survive.
According to the Leukemia & Lymphoma Society, the overall 5-year survival rate for AML, based on data from 2009 to 2015, is 29.4 percent.
Survival rates worsen as you get older. The survival rate 1 year after diagnosis is:
If you need support or information on living with AML, there are resources available. Here are a few of them.
From the American Society of Clinical Oncology:
CancerCare’s Acute Myeloid Leukemia website offers a wide variety of free, professional support services, including:
- financial assistance
- support groups
- educational workshops
AML is an aggressive cancer that affects myeloid blood cells. Its symptoms are related to lowered levels of red blood cells, platelets, and functioning non-lymphocytic white blood cells.
The risk of AML increases with age. It is usually first diagnosed around the age of 68, and is uncommon in people younger than 45.
Chemotherapy is used to kill as many leukemia cells in the blood and bone marrow as possible. This may be followed by radiation therapy and a bone marrow transplant.