Acute myeloid leukemia

Acute myeloid leukemia (AML), also known as acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia or acute nonlymphocytic leukemia, is a fast-growing form of cancer of the blood and bone marrow. AML is the most common type of acute leukemia.

AML is also known as acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia or acute nonlymphocytic leukemia. It occurs when the bone marrow beings to make blasts, cells that have not yet completely matured. These blasts normally develop into white blood cells. However, in AML, these cells do not develop and are unable to ward off infections.

In AML, the bone marrow may also make abnormal red blood cells and platelets. The number of these abnormal cells increases rapidly, and the abnormal (leukemia) cells begin to crowd out the normal white blood cells, red blood cells and platelets that the body needs.

AML types

One of the main things that differentiates AML from the other main forms of leukemia is that it has eight different subtypes, which are based on the cell from which the leukemia developed. The types of acute myelogenous leukemia include:

• Myeloblastic (M0), on special analysis: This is a rare AML subtype that could potentially occur in children and adults. According to a clinical trial published in Blood, it’s defined as having less than 3 percent myeloperoxidase (MPO)— and/or sudan black B (SBB)–positive blasts.
• Myeloblastic (M1), without maturation: This is another rare type of AML. According to the National Center for Advancing Translational Sciences: Genetic and Rare Diseases Information Center (GARD), this type is identified by having more than 90 percent blast cells in the non-erythroid population and no significant myeloid maturation.
• Myeloblastic (M2), with maturation: According to the National Cancer Institute: Surveillance, Epidemiology and End Results (SEER) Program, this type of AML shows evidence of maturation and also has 20 percent or more blasts in either the bone marrow or blood.
• Promyelocytic (M3): This subtype is identified as having malignant promyelocytes with mature myeloid immunophenotype.
• Myelomonocytic (M4): This subtype is categorized as having increased blast cells that represent more than 20 percent of bone marrow or peripheral blood, according to GARD. This subtype also contains 20 to 80 percent of the bone marrow cells having monocytic lineage, a type of white blood cell.
• Monocytic (M5): According to the Journal of Clinical Oncology, monocytic AML is characterized by having at least 80 percent of the impacted blood cells with monocytic lineage.
• Erythroleukemia (M6): This type of AML has a large number of immature cells all within the erythroid (a type of red blood cell) lineage.
• Megakaryocytic (M7): This rare AML type evolves from primitive megakaryoblasts, a type of blood cell.

Acute myeloid leukemia symptoms

Because AML makes abnormal cells that crowd out normal healthy cells, many of its symptoms are a result of the low number of healthy blood cells in the body. Some AML symptoms include:

• Frequent infections and fever: The job of white blood cells is to ward off infections and protect our bodies from foreign germs and bacteria. Because AML reduces the number of healthy white blood cells, the body is not as capable of defending against foreign germs and bacteria. Therefore, patients with AML may have an increased rate of infections and fevers.
• Anemia: Red blood cells carry oxygen throughout the body. The low level of healthy blood cells caused by AML may lead to feeling tired and/or weak, having shortness of breath and looking pale.
• Easy bleeding or bruising: Platelets control bleeding. Having low levels in the blood can lead to easy bleeding or bruising. This can result in the slow healing of cuts, prolonged bleeding from minor cuts and bruises with no clear cause. It can also lead to petechiae, tiny red spots under the skin.
• Joint and bone pain: The increased number of leukemia cells can cause pain in bones, joints or both.
• Dizziness: Patients with a low red blood cell count may feel lightheaded or dizzy.
• Fatigue: Low level of healthy blood cells may result in feeling tired and run down.
• Night sweats: One general symptom of AML may include waking up feeling sweaty during the night.
• Feeling cold: Patients with a low red blood cell count may frequently feel cold.
• Weight loss: A nonspecific symptom of AML may include unexplained weight loss.
• Shortness of breath: Feeling short of breath may occur in patients with a low red blood cell count.
• Swollen lymph nodes: If AML spreads to the lymph nodes, they may feel enlarged, especially around the groin, neck, underarm area and just above the collarbone.

Some AML symptoms are general in nature and don’t, on their own, mean someone has AML, since they may be caused by other health conditions. The patient should always speak to his or her doctor after noticing unexpected health or bodily changes.

Acute myeloid leukemia risk factors

Several known risk factors may increase the lifetime risk of developing acute myeloid leukemia. Risk factors don’t necessarily mean someone will develop AML, but for those who do have one or more risk factors, it’s important to discuss them with their doctor.

Acute myeloid risk factors include:

Age and gender: Although AML may occur at any point in someone’s life, the risk increases with age. According to the American Society of Clinical Oncology (ASCO), around 50 percent of AML patients are 65 years or older when first diagnosed. It’s also more common in males.

Tobacco use: Smoking is also a risk factor that may directly increase the risk of many cancers, including acute myeloid leukemia. Smoking is considered the only lifestyle risk factor for the disease.

Exposure to certain chemicals: Other major risk factors include previous exposure to radiation therapy or chemotherapy from previous cancer treatments. Exposure to cigarette smoke petroleum and benzene, which is found in industrial businesses, also raises the risk of AML.

Family history: In some instances, having a parent or sibling with AML may increase risk. Though the instance is very rare, those with an identical twin who had AML before the age of 1 has a significantly increased risk.

Other risk factors include:

• Certain genetic disorders or mutations, including:
  • Inherited germline mutations
  • Down syndrome
  • Klinefelter syndrome
  • Ataxia-telangiectasia
  • Fanconi anemia
  • Li-Fraumeni syndrome (LFS)
  • Wiskott-Aldrich syndrome
  • Familial platelet disorder
  • Bloom syndrome
• Certain bone marrow disorders, including:
• Essential thrombocytosis
• Myelofibrosis
• Aplastic anemia
• Myelodysplastic syndromes
• Polycythemia vera

Patients concerned about their risk factors should talk to their care team to find out more.

Acute myeloid leukemia treatment options

Treatment for AML may include chemotherapy, radiation therapy, stem cell transplant and/or targeted therapy. Your integrated team of leukemia experts will answer your questions and recommend treatment options based on your unique diagnosis and needs.

A common chemotherapy treatment for AML begins with induction chemotherapy, in which a combination of drugs is used to destroy as many leukemia cells as possible and bring blood counts to normal. This is followed by consolidation chemotherapy, to destroy any remaining leukemia cells that cannot be seen in the blood or bone marrow.

Acute myeloid leukemia survival rate

According to ASCO, AML isn’t common, accounting for approximately 1 percent of all cancers. However, for those who are diagnosed with AML, survival rates vary from patient to patient, based primarily on age and the type of AML.

ASCO estimates that, for patients 20 years of age and younger, the five-year survival rate for AML is 69 percent. The five-year survival rate for patients older than 20 is 27 percent. Survival rates for all cancers are improving over time, thanks to advances in treatment options.

Next topic: What is chronic lymphocytic leukemia?