Acute Myeloid Leukemia

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is AML (acute myeloid leukemia)?

Acute myeloid leukemia (AML) is a type of blood and bone marrow cancer. The term “acute” means it is a fast-growing cancer. To understand the term “myeloid,” it helps to talk about how blood cells develop and mature.

All blood cells come from a common early cell called a stem cell or progenitor cell. These stem cells can turn into myeloid stem cells or lymphoid stem cells. Lymphoid stem cells mature into white blood cells called lymphocytes. Myeloid stem cells can develop into three types of cells—myeloblasts, red blood cells, and platelets. Myeloblasts, in turn, can develop into white blood cells called granulocytes. Granulocytes include neutrophils, basophils and eosinophils.

AML begins in the myeloid stem cell. In most cases, AML affects the myeloblast branch that becomes granulocytes, specifically neutrophils. Less often, AML affects the red blood cell or platelet branches of the myeloid line.

Because of the complexity of the myeloid line, there are several other names for AML. This includes acute non-lymphocytic leukemia, acute myeloblastic leukemia, acute myelocytic leukemia, acute myelogenous leukemia, and acute granulocytic leukemia.

In AML, the myeloblast line typically begins growing out of control in the bone marrow and producing too many neutrophils. This crowds out room for normal cells, including other white blood cells, red blood cells, and platelets. The bone marrow pushes the immature neutrophils out into the blood. Neutrophils are one of the first cells to fight an infection. Normally, they ingest microorganisms and release enzymes that kill them. Immature neutrophils are not capable of doing this. They can also accumulate in organs, including the lymph nodes, spleen, liver, and central nervous system.

The symptoms of AML relate to the effects of immature neutrophils and the crowding out of other healthy cells. This includes frequent infections, anemia, easy bruising and bleeding, swollen lymph nodes, and bone pain.

AML is not a common cancer; it accounts for about 1% of U.S. cancer cases. About 20,000 Americans will be diagnosed with AML this year. Most of these cases will be in adults. AML accounts for about one-third of adult leukemias. It is the second most common leukemia in children.

The risk of AML increases as you age, with the average age at diagnosis being 68 years. The risk is also higher for males, smokers, and people with other blood disorders, genetic disorders, and previous cancer treatment. However, the exact cause of AML is unclear.

Chemotherapy is the main treatment for AML in both adults and children. Other treatments vary depending on your age and other factors. Options may include targeted therapy, stem cell transplant, immunotherapy, and radiation therapy.

Left untreated, AML progresses rapidly and becomes fatal. Often, acute myeloid leukemia causes flu-like symptoms that are not specific. Unlike the flu, AML symptoms will not go away with time. See your doctor if you have persistent or concerning symptoms.

What are the symptoms of acute myeloid leukemia?

Most AML symptoms are due to rapid and abnormal growth of neutrophils. The resulting immature neutrophils are not able to do their job in fighting infections. They also crowd out normal white blood cells, red blood cells, and platelets from the bone marrow. In addition, AML can cause general, nonspecific symptoms that are similar to the flu.

Common symptoms of acute myeloid leukemia

Common symptoms of AML include:

Most of these symptoms are not specific to AML. They are much more common with other diseases and conditions that are not cancerous. The only way to know what is causing your symptoms is to see your doctor for a diagnosis. Make an appointment with your doctor if you have these symptoms and they persist or worsen. In general, finding cancer early offers the best chance for a good prognosis.

What are the acute myeloid leukemia stages?

Staging is an important part of the diagnostic process for cancers that form tumors. It tells doctors about the burden of the cancer—how large it is and whether or not it has spread. This informs treatment options and prognosis.

Leukemias, including AML, do not form tumors and are usually widespread at diagnosis. So, doctors do not stage them. Instead, doctors look at the subtype, a person’s age, and other lab markers to determine prognosis and treatment.

The main way to classify AML subtypes is by the type of cell from which it develops and how mature the cell is. The primary classification system is the French-American-British (FAB) system:

  • M0: Myeloblastic without differentiation

  • M1: Myeloblastic with minimal maturation

  • M2: Myeloblastic with maturation

  • M3: Promyelocytic or APL (acute promyelocytic leukemia)

  • M4: Myelomonocytic

  • M4eos: Myelomonocytic with eosinophils

  • M5a: Monocytic without differentiation (monoblastic)

  • M5b: Monocytic with differentiation

  • M6: Erythroleukemia

  • M7: Megakaryocytic

M0-M5 affects different lines of white blood cells. M6 affects red blood cells. M7 affects platelets. There is also a newer system that the World Health Organization (WHO) uses.

What causes acute myeloid leukemia?

Cancer is the result of DNA mutations or errors in the genes that control cell growth. Sometimes, the errors are inherited from one or both parents before birth. Other times, the errors occur over the course of a lifetime. The chances of an error increase with age, making many cancers more common in older people. In some instances, there is a known cause for the error, such as cancer-causing chemicals (mutagens). But most of the time, the errors are random and there does not appear to be a clear cause.

In AML, a small number of cases are linked to inherited genetic syndromes. Most cases of AML happen due to genetic errors that occur during a person’s lifetime. While there are some known risk factors, AML appears to be mainly random.

In addition, there are many different gene and chromosome errors that can result in AML. This has made it challenging to understand how each error causes leukemia. The exact cause of AML remains unclear.

What are the risk factors for acute myeloid leukemia?

There are several factors that increase the risk of developing AML. Some people who get AML have at least one of these risk factors, but others do not. Known risk factors for AML include:

  • Age: AML is most common in adults 65 years of age or older. It is rare in people younger than 45.

  • Blood disorders: People with myelodysplastic syndrome (MDS), myelofibrosis, polycythemia vera, or thrombocytopenia have a higher risk of AML.

  • Chemical exposure: AML has been linked to certain chemicals, such as benzene.

  • Family history: While there does not appear to be a strong family link, the risk of AML increases if a close relative has it.

  • Genetic syndromes: Several genetic disorders raise the risk of AML. This includes Down syndrome, trisomy 8, ataxia-telangiectasia, Fanconi anemia, Li-Fraumeni syndrome, and neurofibromatosis type 1, among others.

  • High-dose radiation exposure: Very high levels of radiation increase the risk of AML. This includes nuclear reactor accident survivors and cancer patients treated with very high doses.

  • Previous cancer treatment: People who have had certain chemotherapy (chemo) drugs for other cancers have a higher risk of AML. This includes alkylating agents and topoisomerase II inhibitors. Radiation therapy may further increase the risk.

  • Sex: AML is more common in men than women, for unknown reasons.

  • Tobacco use: AML is more common in smokers than nonsmokers.

Reducing your risk of acute myeloid leukemia

Preventing cancer relies on changing risk factors that are under your control. Unfortunately, most people with AML do not have risk factors. Even when they do have risk factors, most are not controllable. The two exceptions are tobacco use and chemical exposure.

Quitting smoking is the single biggest step you can take to reduce your risk of AML. It will also reduce your risk of several other cancers, heart disease and stroke. If you have tried without success, try again. Talk with your doctor about tools and strategies you can use to quit for good.

If you work with benzene, follow the safety precautions for handling this chemical.

How do doctors diagnose acute myeloid leukemia?

To diagnose your condition, your doctor will take a thorough medical history. This will likely include asking you several questions related to your symptoms including:

  • What symptoms are you experiencing?

  • How long have you had these symptoms?

  • Are your symptoms constant or do they come and go?

  • What, if anything, seems to make your symptoms better or worse?

  • Have you ever been diagnosed or treated for another type of cancer?

  • Do you have a family history of any type of cancer, including leukemia?

  • Do you smoke?

  • What other medical conditions do you have, including blood disorders?

Your doctor will also perform a physical exam looking for swollen lymph nodes and signs of bleeding or bruising. The exam will also focus on your abdomen, eyes, mouth, skin, and nervous system. Using the results, your doctor may recommend testing including:

  • Blood tests, which are usually the first type of testing. This includes blood chemistry, liver and kidney function tests, blood clotting tests, and a complete blood count to measure the number of white blood cells, red blood cells, and platelets. A lab may also look at a blood sample under a microscope to check for immature cells.

  • Bone marrow aspiration or biopsy to examine it for the presence of leukemia cells

  • Lumbar puncture, or spinal tap, to see if cancer has spread to the brain or spinal cord

  • Molecular and genetic testing to look for specific genetic and chromosomal changes in leukemia cells

What are the treatments for acute myeloid leukemia?

AML treatment consists of two phases:

  • Remission induction: The goal of this first phase is to kill leukemia cells and bring about remission. This means the bone marrow looks normal, blood counts are normal, and there are no symptoms. Induction usually cannot get rid of all leukemia cells in the body. Without the second treatment phase, AML is likely to return.

  • Consolidation or post-remission: The goal of this second phase is to eliminate any leukemia cells remaining in the body if induction was successful. This phase is vital for preventing relapse.

Some people need a treatment called leukapheresis before beginning remission induction. It uses a special machine to remove white blood cells from the blood. It may be necessary when there are so many white blood cells that they interfere with blood circulation. It can provide relief until remission induction takes effect.

Chemotherapy is the main treatment in both phases of AML treatment. Depending on each patient’s AML subtype, age and health, chemotherapy will be a combination of 2 or 3 chemo drugs during remission induction. Targeted therapy may be part of remission induction when certain genetic changes are present. If AML is in the brain or spinal cord, doctors may also use radiation and give chemo directly into the CSF (cerebrospinal fluid).

It may be necessary to stay in the hospital during induction chemotherapy. The drug regimens can make the levels of blood cells dangerously low. Doctors may need to use blood product transfusions and IV antibiotics to prevent serious illness.

Consolidation therapy is typically more intense than remission induction. It typically involves high-dose chemo and a stem cell transplant. If targeted therapy was part of remission induction, doctors usually continue it during consolidation.

The treatment regimen can vary slightly depending on the AML subtype. Acute promyelocytic leukemia (APL) subtype has a completely different treatment regimen than other types of AML.

When making treatment decisions, it is important to work with a doctor who knows AML well. Successful AML treatment depends heavily on the results of the first phase.

Alternative treatments for acute myeloid leukemia 

You should not rely on alternative treatments alone to treat AML. However, they can help improve comfort during traditional treatment. Possible options for supportive treatments include:

  • Acupuncture

  • Exercise and regular physical activity

  • Massage therapy

  • Relaxation techniques, including meditation, guided imagery, and mind-body activities like yoga and tai chi

Talk with your doctor before starting any alternative treatment. You need to make sure they will not interfere with or increase the risk of side effects from your traditional treatments.

How does acute myeloid leukemia affect quality of life?

AML is an aggressive form of leukemia. Compared to other leukemias, the prognosis and survival is often poor. This can result in depression, anxiety, and a poor quality of life.

Older patients, in particular, may need to make difficult decisions about intensive vs. non-intensive treatment. Healthcare providers may have preconceived notions about the influence of these decisions on quality of life. However, research suggests that patients on either path have similar quality of life experiences. Anxiety symptoms and overall quality of life seems to improve regardless of the intensity of therapy. This may be a comfort to people facing this kind of decision.

Coping and support resources are an important part of any cancer treatment journey. Treatment centers have a variety of counselors, therapists, chaplains and social workers to help. Support groups are another option for dealing with a cancer diagnosis and its treatment. They offer a place to share your feelings and hear from people having the same experience.

What are the potential complications of acute myeloid leukemia?

The main complications of AML are poor treatment response and relapse or recurrence. About two-thirds of people who get standard induction treatment achieve complete remission. This means the bone marrow contains fewer than 5% blast cells (immature cells), blood counts are normal, and there are no signs or symptoms of AML. People who achieve this remission go on to receive consolidation therapy.

The risk of relapse decreases with successful consolidation or post-remission therapy. About half of people who get consolidation therapy achieve long-term remission. The other half will have a relapse. Monitoring for relapse is a vital part of follow-up care during survivorship. These checks can be very stressful for you and your family members. Using support resources can help everyone deal with the necessary follow-up care.

For APL, about 90% of people achieve complete remission with induction therapy. With consolidation therapy, about 80 to 90% achieve long-term remission.

What is the survival rate and prognosis for acute myeloid leukemia?

Several factors affect AML prognosis and the risk of relapse. The subtype of AML is one of them. Other prognostic factors include:

  • Age: People over age 60 tend to have a poorer prognosis than younger people. Older people are more likely to have unfavorable chromosome abnormalities and medical conditions that may prevent intensive treatment.

  • Cell markers: Leukemia cells with the CD34 protein and/or the P-glycoprotein (MDR1 gene product) are an unfavorable factor.

  • Central nervous system involvement: AML in the brain or spinal cord is unfavorable.

  • Chromosome abnormalities: With AML, there are both favorable and unfavorable chromosome abnormalities. Two of the three favorable ones most often occur with M2 and M3.

  • Gene mutations: Like chromosome abnormalities, there are favorable and unfavorable gene mutations. Changes in the NPM1 gene without any other changes is favorable. Changes in both copies of the CEBPA gene is also favorable.

  • Infection: Having a blood infection at the time of diagnosis is unfavorable.

  • Prior blood disorder or cancer treatment: When AML develops from another blood disorder, such as MDS, it is unfavorable. Developing AML after a previous cancer treatment is also unfavorable.

  • White blood cell count: In general, lower white blood cell counts at diagnosis are favorable.

In general, AML has a poorer prognosis than other forms of leukemia. In people 20 years of age and older, the 5-year AML leukemia survival rate is 26%. In younger people, it is 68%.

Keep in mind, treatment response rates, cancer prognosis, and 5-year survival statistics are estimates. They cannot tell you how long you will live. There are many factors that play a role in life expectancy, including overall health. Your doctor is the best source of information about your disease and prognosis. Your doctor is also best able to advise you about ways to improve your outlook.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jun 18
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