masthead abstract

What is Acute Myeloid Leukemia (AML)?

Upon diagnosis with AML cancer, many people simply want to know what is acute myeloid leukemia. Acute Myeloid Leukemia (AML) is a cancer of the blood and bone marrow and mainly affects adults. AML is characterized by the excessive growth of immature blood forming cells in the bone marrow. AML is the most common acute leukemia in adults.

Cancer can start in nearly any part of the human body, and is when cells begin to grow out of control.  Leukemia is a type of cancer that starts in cells that would normally develop into various types of blood cells.  There are several types of leukemia and several treatment options and resources for help with this type of cancer.

Acute myeloid leukemia (AML) starts in the bone marrow which is the soft inner part of certain bones, where new blood cells are made. Most often it moves into the blood quickly. It can sometimes spread to other parts of the body including the liver, spleen, lymph nodes, even central nervous system (brain and spinal cord), and testicles. Most often, Adult Acute Myeloid Leukemia develops from cells that would turn into white blood cells (other than lymphocytes), but sometimes AML develops in other types of blood-forming cells.

Another name for AML is Acute myelogenous leukemia, a cancer of the blood and bone marrow.  Bone marrow is the spongy tissue inside bones where blood cells are made.

The word “acute” refers to 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 myeloid leukemia is also known as acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia and acute nonlymphocytic leukemia.

What is Relapsed & Refractory Acute Myeloid Leukemia?

AML is a rapidly advancing cancer. Sometimes, leukemia cells return after initial treatment of the cancer (relapse) or are resistant to treatment (refractory).

Relapsed AML (Relapsed Acute Myeloid Leukemia) is when the number of leukemia cells in your bone marrow has gone up and you have fewer healthy cells in your blood.

AML relapse can happen if:

  • The cancer didn’t respond well to the first treatment you tried
  • Treatment didn’t get rid of all the leukemia cells
  • Cancer cells spread to other parts of your body and were too small for tests to pick up

*AML can relapse months or years after your first treatment.

Refractory AML means the leukemia did not respond to treatment. Complete remission has not been reached because the chemotherapy drugs did not kill enough leukemia cells in the treatment.

Both relapsed and refractory AML need more treatment for the cancer to reach complete remission.

Normal bone marrow, red blood cells, and white blood cells

To understand leukemia, it helps patients to know about the blood and lymph systems involved in this disease. There are 3 main types of blood cells. They are red blood cells (RBCs), platelets, and white blood cells (WBCs).

Normal Bone Marrow

Bone marrow is the soft inner part of some bones, like the skull, shoulder blades, ribs, pelvis, and backbones. A small number of blood stem cells, more mature blood-forming cells, fat cells, and supporting tissues make up the bone marrow. 

Normal Red Blood Cells

Normal red blood cells carry oxygen from the lungs to all other tissues in the body, and take carbon dioxide back to the lungs to be removed. Having too few red blood cells (anemia) can make you feel tired, weak, and short of breath because your body tissues aren’t getting enough oxygen.

Normal White Blood Cells

Normal white blood cells help the body fight infections. Having too few white blood cells (neutropenia) lowers your immune system and can make you more likely to get an infection.

Types of white blood cells

Types of white blood cells are granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells). A complete blood cell (CBC) test usually checks the number of white blood cells in the blood. It may be used to look for conditions such as infection, inflammation, allergies, and leukemia. Also called leukocyte and WBC.

AML (Acute Myeloid Leukemia) Types 

There are many subtypes of Acute Myeloid Leukemia (AML). Your doctor can provide more information on your specific case and leukemia treatment option. Most AML subtypes are based on how mature (developed) the cancer cells are at the time of diagnosis and how different they are from normal cells.

In the 1970s, a group of French, American, and British leukemia experts divided AML into subtypes, M0 through M7, based on the type of cell the leukemia develops from and how mature the cells are. This is the French-American-British (FAB) classification of AML. This classification was based largely on how the leukemia cells looked under the microscope after routine staining.

  • M0 AML: Undifferentiated acute myeloblastic leukemia.
  • M1 AML: Acute myeloblastic leukemia with minimal maturation
  • M2 AML: Acute myeloblastic leukemia with maturation
  • M3 AML: Acute promyelocytic leukemia (APL)
  • M4 AML: Acute myelomonocytic leukemia
  • M4 AML eos: Acute myelomonocytic leukemia with eosinophilia
  • M5 AML: Acute monocytic leukemia
  • M6 AML: Acute erythroid leukemia
  • M7 AML: Acute megakaryoblastic leukemia

Subtypes M0 through M5 all start in immature forms of white blood cells. M6 AML (Acute Myeloid Leukemia)  starts in very immature forms of red blood cells, while M7 AML starts in immature forms of cells that make platelets.

What Are the Symptoms of Adult Acute Myeloid Leukemia

Often people diagnosed with acute myeloid leukemia want to know the symptoms of AML and at what stage symptoms of this cancer are likely to be experienced.  Many of these AML symptoms are common to other diseases, however, if you are concerned about any of these symptoms, it is always wise to consult your doctor.

  • 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 (Adult Acute Myeloid Leukemia) 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.
  • Loss of appetite from AML: This may also result in weight loss from the loss of appetite from acute myeloid leukemia symptoms.
  • Fullness or swelling in the abdomen:  This is usually caused by an enlarged spleen or liver as the cancer progresses through the stages of AML.

Stages of AML

There are two common staging systems used for Acute Myeloid Leukemia (AML). Your doctor can provide more information on your specific case and leukemia treatment option.

In all stages of AML, the blood contains too many lymphocytes, which indicates that cancer is present.  This is called lymphocytosis.

  • Stage 0 of Acute Myeloid Leukemia Cancer. In this stage of AML, the other blood counts are close to normal, and there are no other symptoms of leukemia. The cancer is slow growing, and this stage is low risk. This means people tend to have longer survival rates and have no or few symptoms of acute myeloid leukemia.
  • Stage I of Acute Myeloid Leukemia Cancer. While other organs are normal size, the lymph nodes are larger than normal. The red blood cell and platelet counts are close to normal even as the acute myeloid leukemia begins to grow.
  • Stage II of Acute Myeloid Leukemia Cancer.  Splenomegaly, where the spleen is swollen or enlarged, develops. Hepatomegaly, where the liver may be swollen, can also develop as acute myeloid leukemia develops. The lymph nodes may also be larger than normal. Red blood cell and platelet counts are close to normal.
  • Stage III of Acute Myeloid Leukemia Cancer.  The blood has too few red blood cells. This is called anemia and is a symptom of acute myeloid leukemia. The lymph nodes, liver, or spleen may be larger than normal. Platelet counts are close to normal.
  • Stage IV of Acute Myeloid Leukemia Cancer. The blood has too many lymphocytes. It also has too few platelets. This is called thrombocytopenia. The lymph nodes, liver, or spleen may be larger than normal in this stage of AML. The blood may have too few red blood cells.

Treatment for AML

Treatment for various types of AML may include:

Chemotherapy for AML

Chemotherapy (chemo) is the use of anti-cancer drugs that are injected into a vein, under the skin, or into the cerebrospinal fluid (CSF), or drugs that are taken by mouth to destroy or control cancer cells. Except when given into the CSF, these drugs enter the bloodstream and reach all areas of the body, making this myeloid leukemia treatment  useful for cancers such as leukemia that spread throughout the body.

Bone marrow transplant for AML (Adult Acute Myeloid Leukemia treatment)

In a bone marrow transplant (stem cell transplant), healthy stem cells from bone marrow are infused into your body. A transplant can help replace damaged bone marrow cells and, in turn, make healthy blood cells.

In a 2021 article  published in Frontiers in Immunology, researchers found that, “A bone marrow transplant can improve survival rates for some people with acute myeloid leukemia (AML). Replacing damaged cells with healthy ones can reduce a person’s risk for bone marrow damage and relapse.”

New treatments for AML

New AML treatments such as investigational drugs and medicine given in AML clinical trials can greatly benefit the patient.