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Acute Myeloid Leukemia - Stages and Types of Acute Myeloid Leukemia

Home> Acute myeloid leukaemia> Overview and Types

AML is an aggressive condition of the bone marrow and may be life-threatening if left untreated. The risk increases with age, and men have a higher risk than women. The disease is classified based on various systems. Almost 50% of the patients who achieve remission may have a recurrence.

What Is Acute Myeloid Leukemia?

Acute myeloid leukemia, which is often called AML blood cancer, is a cancer affecting the bone marrow and blood. Patients with AML rapidly develop abnormal blood cells, i.e., platelets, red blood cells, and white blood cells. The origin of AML is in the myeloid cells that are responsible for the production of blood cells. Symptoms include frequent infections, shortness of breath, and bleeding. Diagnosis of the condition is through bone marrow and blood testing. However, other methods, such as imaging tests, may also be used to detect the involvement of other organs, especially in the final stages of acute myeloid leukemia. The prognosis of AML depends on several factors, including the type of AML, overall health, and the patient's response to treatment. AML cancer treatment involves chemotherapy, radiation therapy, and targeted therapy.

How Common is Acute Myeloid Leukemia (AML)?

Acute myeloid leukemia is a relatively rare type of leukemia compared to other chronic types of leukemia. The risk of this disease increases with age, and men are at higher risk for AML compared to women. The incidence varies with geographical location. Further, there is an increasing proportion of AML among different types of leukemia. For instance, the ratio for AML was 18% of total leukemia cases globally. It increased to 23% in the year 2017. In India, the annual incidence is 2-3 per 100,000. AML in India is less than 1/100,000 < 30 years of age and 17/100,000 by 75 years. It accounts for < 10% of all leukemia cases in children aged <10 years and 25-30% in people aged between 10 and 15 years.

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What are Types of Acute Myeloid Leukemia (AML)?

There are several methods for classifying AML. The World Health Organization system, updated in 2016, classifies AML into the following types of acute myeloid leukemia:

AML with certain genetic abnormalities

  • AML with an inversion or translocation in chromosome 16 [t(16;16) or inv(16)]
  • AML with a translocation among chromosomes 8 and 21 [t(8;21)]
  • Acute promyelocytic leukemia with PML-RARA fusion gene
  • AML with a translocation in chromosomes 6 and 9 [t(6:9)]
  • AML with a translocation in chromosomes 9 and 11 [t(9;11)]
  • AML (megakaryoblastic) having translocation between chromosomes 1 and 22 [t(1:22)]
  • AML having translocation or inversion in chromosome 3 [t(3;3) or inv(3)]
  • AML having biallelic mutations of the CEBPA gene
  • AML having a mutation in the NPM1 gene

AML with myelodysplasia-related changes

AML related to previous chemotherapy or radiation caused by chemotherapy or radiation therapy as part of a cancer treatment strategy

AML not otherwise specified

  • AML with minimal differentiation (FAB M0)
  • AML without maturation (FAB M1)
  • AML with maturation (FAB M2)
  • Acute myelomonocytic leukemia (FAB M4)
  • Acute monoblastic/monocytic leukemia (FAB M5)
  • Pure erythroid leukemia (FAB M6)
  • Acute megakaryoblastic leukemia (FAB M7)
  • Acute basophilic leukemia
  • Acute panmyelosis with fibrosis

Myeloid sarcoma

Myeloid proliferations related to Down syndrome occur in patients with Down Syndrome

What are the Acute Myeloid Leukemia Stages?

The following are the different stages of acute myeloid leukemia:

Untreated

Untreated AML disease is a newly diagnosed disease, and the patients have not undergone any treatment. The disease is characterized by a few blood cells, i.e., platelets, red blood cells, and white blood cells. The blood sample contains immature cells, also known as blasts. In cases where leukemia is diagnosed, these blast cells are known as leukemia cells. Patients have ≥20% of the cells as blast cells in the bone marrow.

Active disease

This stage is characterized by the presence of at least 5% of the cells in the bone marrow as blast cells. This stage may occur during treatment or when the cancer recurs after treatment completion.

In remission

Remission may be divided into complete remission and particle remission. Complete remission is characterized by a platelet count greater than 100 x 109/L and a neutrophil count greater than 1 x 109/L without blood transfusion, the presence of less than 5% blast cells in the bone marrow, no AML symptoms, such as fatigue, weight loss, and fever, and the absence of any signs and symptoms of leukemia in the spinal cord and brain. Partial remission occurs when the patients have less than 2% of the bone marrow cells as blast cells and there is normal bone marrow functioning.

Measurable residual disease

Leukemia cells can be identified through conventional laboratory tests, such as microscopy, and highly sensitive tests, e.g., polymerase chain reaction and flow cytometry. After the AML cancer treatment, some leukemia cells are still present in the blood. However, these cells are not identified with conventional laboratory tests but can be detected through highly sensitive techniques. AML identified through highly sensitive techniques but not through traditional techniques is known as measurable residual disease or minimal residual disease. It assists clinicians in determining the response to treatment and predicts the risk of cancer recurrence.

Relapsed

Relapsed AML is when the cancer recurs after remission or complete treatment. Relapsed AML is characterized by at least 5% of the bone marrow cells being blast cells, and the proportion of blast cells continues to rise.

Refractory

Refractory AML is when the AML does not respond to the available treatment even after intensification. The patients are said to have refractory AML if they fail to achieve complete remission after a couple of cycles of induction chemotherapy.



Conclusion

Acute myeloid leukemia is characterized by a low count of healthy blood cells. Patients experience weakness and fatigue and have an increased risk of infection. Classification of the types of acute myeloid leukemia may be based on the cause of acute myeloid cancer, such as genetic abnormalities or cancer therapies. Stages of AML leukemia include untreated, active, relapse, remission, and refractory.

Frequently Asked Questions

Can acute myeloid cancer be cured?

Approximately 50 to 80% of the individuals with AML can achieve complete remission. Patients below the age of 60 have a higher chance of achieving remission. Other factors also affect complete remission.

Some of the common leukemia symptoms include weakness, fatigue, shortness of breath, infection, fever, and bleeding gums.

AML is an aggressive cancer. If not treated, it may lead to life-threatening complications. AML should be diagnosed and managed as early as possible.

Malignant cells formed in AML have the potential to spread to various body organs, such as the spleen, lymph nodes, brain, liver, gums, and skin.