Leukemia: Patient Education

Cancer Facts

Acute Lymphocytic Leukemia (ALL)

According to the American Cancer Society, “The risk for developing ALL is highest in children between 2 and 4 years of age. The risk then declines slowly until the mid-20s, and begins to rise again slowly after age 50.”

Acute Myeloid Leukemia (AML)

According to the American Cancer Society, “Acute myeloid leukemia is generally a disease of older people and is uncommon before the age of 40. The average age of a patient with AML is about 67 years.”

Chronic Lymphocytic Leukemia (CLL)

According to the American Cancer Society, “CLL mainly affects older adults. The average age at the time of diagnosis is around 72 years. It is rarely seen in people under age 40, and is extremely rare in children.”

Chronic Myeloid Leukemia (CML)

According to the American Cancer Society, “CML accounts for about 10 percent to 15 percent of all leukemias. The average person's lifetime risk of getting CML is about 1 in 625. This disease is slightly more common in men than in women. It is also more common in whites than in African-Americans.”

Overview

Leukemia is a group of malignant cells that starts in the white blood cells in your bone marrow. Your bone marrow is the spongy center of your bones, where blood cells grow.

Leukemia means “white blood.” Your body uses your white blood cells (leukocytes) to fight off infections and other foreign substances.

How Leukemia Develops

Your blood cells grow from cells in your bone marrow called stem cells. These stem cells develop into:

  • White blood cells — fight infection
  • Red blood cells — carry oxygen throughout your body
  • Platelets — help form blood clots that prevent bleeding

As your blood cells grow old, they die; your body generates new blood cells in a continual process of renewal.

In the process of regeneration of blood cells, a stem cell may develop into:

  • Myeloid stem cell ➔ myeloid blast
    • The myeloid blast can become:
      • Red blood cell
      • Platelet
      • White blood cell
  • Lymphoid stem cell ➔ lymphoid blast
    • Lymphoid blast can become
      • White blood cell
        • B-cell
        • T-cell

With leukemia, your bone marrow begins to make abnormal white blood cells. These leukemia cells multiply without dying, taking over the healthy white blood cells, red blood cells and platelets. in effect, leukemia is an uncontrolled growth of white blood cells.

In most case, leukemia spreads through your blood quickly. It can then spread through your lymph system to your:

  • Lymph nodes
  • Liver
  • Spleen
  • Central nervous system (brain and spinal cord)
  • Testicles (males)

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Classifications of Leukemia

There are two classes of leukemia based on their severity and growth rate:

Acute Leukemia “Acute” = Fast Growing

  • Leukemia cells quit working as healthy cells
  • Progresses rapidly
  • Worsens quickly

Chronic Leukemia “Chronic” = Slow Growing

  • Leukemia cells function as healthy cells for a while
  • Progresses slowly
  • Few symptoms at first
  • Worsens gradually

Leukemia is also classified by the types of white blood cells affected:

Lymphocytic

Also called:

  • Lymphoid
  • Lymphoblastic

Myeloid

Also called:

  • Myelogenous
  • Myeloblastic

Types of Leukemia

The four most common types of leukemia are:

  • Acute lymphocytic leukemia (ALL)
    • Affects lymphoid cells
    • Usually grows quickly and requires immediate treatment
    • Affects adults and children
  • Acute myeloid leukemia (AML)
    • Affects myeloid cells
    • Usually grows quickly and requires immediate treatment
    • Affects adults and children
  • Chronic lymphocytic leukemia (CLL)
    • Most common form of leukemia
    • Affects lymphoid cells
    • Usually slow growing
    • Rarely affects children
  • Chronic myeloid leukemia (CML)
    • Affects myeloid cells
    • Initially slow growing
    • Usually affects adults

Less common types of leukemia include:

  • Hairy cell leukemia
  • Chronic myelomonocytic leukemia (CMML)
  • Juvenile myelomonocytic leukemia (JMML) 

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Related Resources

All Leukemias

Acute Lymphocytic Leukemia (ALL)

Acute Myeloid Leukemia (AML)

Chronic Lymphocytic Leukemia (CLL)

Chronic Myeloid Leukemia (CML)

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