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Leukemia

See Also:
Leukemia: Introduction & Pictures
Leukemia: 4 Types & Stages
Leukemia: Causes & Risk Factors
Leukemia: Signs & Symptoms
Leukemia: Medical Tests & Diagnosis
Leukemia: Treatment Options
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Acute Myeloid Leukemia (AML)

Acute myeloid leukemia, also called acute myelogenous, acute myeloblastic, acute granulocytic, or acute non-lymphocytic leukemia, is a bone marrow and blood cancer caused by an increased number of myeloblasts. AML occurs when leukemia affects the myeloid cells in the bone marrow which are cells that, under normal conditions, turn into red blood cells, white blood cells (that are not leukocytes), and platelets.

According to the National Cancer Institue, 12,330 people were diagnosed with AML in 2010, and about 9,000 people will die from it. The five year survival rate is about 24 percent. AML is a leukemia that can strike in both children adults, but occurs more often in adults. About 1 in 5 cases of childhood leukemia is AML.

Of the two main types of acute leukemia, AML is the most common in adults. ALL is considerd more commonly occuring in children. The median age at diagnosis is 67 years old. Unfortunately, this type of leukemia progresses quickly if not treated.

Normally, the body produces three types of blood cells, called mature blood cells.

  1. Red blood cells, which carry oxygen to all the body tissues.

  2. White blood cells, which fight against infections.

  3. Platelets, which control bleeding by forming blood clots.

Mature blood cells develop from immature bone marrow cells called stem cells. When acute myeloid leukemia occurs, too many bone marrow stem cells develop into myeloblasts (a type of white blood cells). This phenomenon is caused by a genetic mutation in the stem cell's DNA, a mutation that is not present at birth, and it can develop at any time during one's life span.

Subtypes of AML

The old subtype classification system was called the French American British (FAB) system which divided AML into 8 subtypes.

Type Name
M0 Minimally differentiated acute myeloblastic leukemia
M1 Acute myeloblastic leukemia, without maturation
M2 Acute myeloblastic leukemia, with granulocytic maturation
M3 Promyelocytic, or acute promyelocytic leukemia (APL)
M4 Acute myelomonocytic leukemia
M4eo Myelomonocytic together with bone marrow eosinophilia
M5 Acute monoblastic leukemia (M5a) or acute monocytic leukemia (M5b)
M6 Acute erythroid leukemias, including erythroleukemia (M6a) and very rare pure erythroid leukemia (M6b)
M7 Acute megakaryoblastic leukemia
M8 Acute basophilic leukemia

The World Health Organization (WHO) has come out with a new classification system which will probably replace the old subtyping system. It includes:

Name Description
AML with characteristic genetic abnormalities Includes:
  • AML with translocations between chromosome 8 and 21 [t(8;21)]
  • AML with inversions in chromosome 16 [inv(16)]
  • AML with translocations between chromosome 15 and 17 [t(15;17)]

Patients with AML in this category generally have a high rate of remission and a better prognosis compared to other types of AML.

AML with multilineage dysplasia This category includes patients who have had a prior myelodysplastic syndrome (MDS) or myeloproliferative disease (MPD) that transforms into AML. This category of AML occurs most often in elderly patients and often has a worse prognosis.
AML and MDS, therapy-related This category includes patients who have had prior chemotherapy and/or radiation and subsequently develop AML or MDS. These leukemias may be characterized by specific chromosomal abnormalities, and often carry a worse prognosis.
AML not otherwise categorized Includes subtypes of AML that do not fall into the above categories.

Besides these two subtyping classification systems, Acute Myeloid Leukemia is often looked at as Chilldhood AML, and Adult AML.

I. Childhood Acute Myeloid Leukemia

Medical researchers could not identify the exact causes of acute myeloid leukemia, but the evidence from clinical trials and medical experience built up over time reveals strong connections between several risk factors and childhood acute myeloid leukemia. These risk factors include:

  • Family history: If there is a sibling with leukemia.
  • Race: AML is more common among Hispanics.
  • Being exposed to cigarette smoke or alcohol before birth.
  • Chemotherapy or medical treatment with drugs that weaken the immune system.
  • Exposure to ionizing radiation.
  • Exposure to chemicals
  • Genetic medical disorders (ex: Down syndrome)
  • Having a medical history of myelodysplastic syndrome (also called pre-leukemia) or aplastic anemia.
 

Child Symptoms: The symptoms can vary from patient to patient depending on the number of leukemia cells and the area of the body where the leukemia cells collect. The most common symptoms include:

  • Fever with or without infection
  • Breathing difficulties (shortness of breath)
  • Feeling tired
  • Weakness
  • Easy bleeding and bruising
  • Small red spots beneath the skin
  • Bone or joint pain
  • Discomfort below the ribs (pain or fullness sensations)
  • Painless blue or purple lumps (called leukemia cutis) in the neck, underarms, stomach, groin or eyes area.

Once leukemia is diagnosed, medical tests are conducted to establish the leukemia stages (the extent or spread of leukemia). Childhood acute myeloid leukemia is not classified through any standard staging system, but is divided in three phases:

Phases: (similar to stages)

1. Untreated: In this phase, leukemia has just been diagnosed and the treatment has focused only to relieve symptoms like fever, pain, and bleeding. The main characteristics of this phase are: 1) more than 20 percent of the bone marrow cells are leukemia cells, and 2) some leukemia signs and symptoms are present.

2. Remission: In this phase, leukemia has been treated. The main characteristics of this phase are: 1) less than 5 percent of the bone marrow cells are leukemia cells, and 2) there are no more signs and symptoms of leukemia.

3. Recurrent: In this phase, leukemia has recurred (relapsed, came back) after it was treated.

II. Adult Acute Myeloid Leukemia

AML in adults is the most common form of leukemia in adults.

Although scientists do not know what causes leukemia, medical researchers have identified a number of factors that may place a person at increased risk for acute myeloid leukemia. These risk factors include:

  • Gender: AML is more common among males.
  • Past medical treatments such as chemotherapy or radiotherapy.
  • Being an active smoker, especially after the age of 60.
  • Being treated for childhood acute myeloid leukemia in the past.
  • Having a medical history of blood disorders such as myelodysplastic syndrome (also called pre-leukemia).
  • Exposure to high doses of radiation (like atomic bomb).
  • Exposure to chemicals.

Adult Symptoms: Some of the most common symptoms of acute myeloid leukemia are:

  • Fever
  • Breathing difficulties (short breathing)
  • Easy bleeding when bruising
  • Small red spots beneath the skin
  • Feeling tired
  • Weakness
  • Unexplained weight loss
  • Loss of appetite

Adult AML Phases (similar to stages)

Once the leukemia is diagnosed, medical tests are conducted to establish the leukemia stages (the extent or progression of the disease). Adult acute myeloid leukemia is not classified through any standard staging system, but is divided in three phases:

1. Untreated adult AML: In this phase, leukemia has been diagnosed and the treatment focuses only on relieving the symptoms (fever, bleeding, and pain). The main characteristics of this phase are: 1) around 20 percent of the bone marrow cells are leukemia cells, and 2) some leukemia signs and symptoms are present.

2. Adult AML in remission: In this phase, leukemia has been treated. The main characteristics of this phase are: 1) less than 5 percent of the bone marrow cells are leukemia cells, and 2) there are no signs or symptoms of leukemia.

3. Recurrent AML: In this phase, leukemia has recurred (relapsed) after it was treated.

Learn more about Treatment Options for AML

See Also:
Leukemia: Introduction & Pictures
Leukemia: 4 Types & Stages
Leukemia: Causes & Risk Factors
Leukemia: Signs & Symptoms
Leukemia: Medical Tests & Diagnosis
Leukemia: Treatment Options
Cancer Search Engine

Related: (opening in new windows)

Article by Alina Morrow, MS
Medical Writer
OmniMedicalSearch.com

   

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Page Last Modified:
12/10/2010