What is Chronic Myeloid Leukemia (CML)?

Learning you have CML is tough. Especially because many people have no symptoms when they are diagnosed.

But chances are you're not one to take your health problems lying down. Breaking down the disease into its basics may help you understand the disease. Beginning with the name.

Chronic myeloid leukemia (CML): what's in the name?

a slow-growing condition that doesn't go away.
Myeloid (or myelogenous)
related to the bone marrow, the spongy tissue that fills the large bones and makes blood cells.
a cancer of the blood cells, mainly white blood cells.

Put it all together and you have a slow-growing type of cancer that affects those cells in the bone marrow that normally go on to form white blood cells.

Think of the bone marrow as the nursery where the blood celIs are born. Healthy cells all have their job to do.

Undeveloped or immature white blood cells are called blast cells. When you have CML, the bone marrow makes uncontrolled numbers of abnormal blast cells. These are the leukemia cells, or "blast" leukemia cells. They don't mature. They don't fight infections like regular mature white blood cells. These immature cells live longer, crowding out not only healthy white blood cells, but red blood cells and platelets as well.

Acute leukemia vs. chronic leukemia

Here's a quick summary of the differences between acute and chronic leukemias. One of the differences is that acute leukemias grow faster. Chronic leukemias are slower growing. Acute leukemia results in the rapid buildup of immature, functionless cells in the marrow and blood. The immature leukemic cells often halt production of normal red blood cells, white blood cells, and platelets. In chronic leukemia, progress is slower, so that greater numbers of more mature, functional cells may continue to be made.

Chronic myeloid leukemia (CML) is a chronic leukemia that affects a specific cell type, myeloid cells, and is associated with a particular chromosomal abnormality called the Philadelphia (Ph) chromosome. Even though abnormal cells are produced, because the disease grows slowly, your body can still continue to make mature, functional cells. Under a physician's care, patients can be treated for this serious chronic disease.

Compare this diagram of bone marrow with and without leukemia cells. You can see how the numbers of abnormal blast cells can clog the bone marrow and interfere with the function of the bone marrow itself as well as formation of normal cells.

Comparing normal bone marrow and diseased bone marrow clogged with leukemia cells

Chronic phase CML: diagnosis and prognosis

First, the diagnosis:

  • About 90% of people with CML are diagnosed in the chronic phase.
  • Many people have few or no symptoms of CML when they're diagnosed.
  • CML may be detected through routine blood tests before any symptoms
    are noticeable.
  • The goal of treatment for people diagnosed in the chronic phase is to keep them in this phase and stop the disease from progressing to the next phase, called "accelerated" phase, or even what's called a "blast crisis".
  • What about the prognosis? It's important to talk to your doctor about your prognosis because it is dependent upon a number of factors, including which treatment you are taking. CML is a chronic disease which, in most cases, cannot be cured. So people tend to undergo continuous treatment for the rest of their lives.

This Web site is not meant to replace a discussion with your doctor, who is your most important source for information.

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