What Is Chronic Myeloid Leukemia?
Chronic myeloid leukemia (CML) is a cancer of the blood in which too many granulocytes, a type of white blood cell, are produced in bone marrow. Normally, bone marrow cells mature into several different types of blood cells. CML affects the young blood cells (called blasts).
An estimated 4,870 new cases of CML were diagnosed in 2010, according to the American Cancer Society. CML is most common in older adults. The average age of diagnosis is about 55 to 60 years, with children only making up 2 percent of cases, according to the American Cancer Society.
The main function of granulocytes is to destroy bacteria. The blasts do not completely mature and become too numerous. They live longer than normal granulocytes and accumulate in the bone marrow and blood.
Initially in CML, there is a gradual increase in mature, abnormal myeloid cells in the bone marrow. These cells eventually spill into the blood and other organs, causing symptoms, such as fatigue from anemia or an enlarged spleen.
The increase in leukemia cell numbers occurs slowly at first and is referred to as the chronic phase. Eventually, the leukemia cells begin to increase more rapidly, resulting in the accelerated and blastic phases. CML can occur over a period of months or years.
Like most cancers, early detection and treatment can help control the disease or eliminate it from your body.
This content was last reviewed
August 15, 2010 by Dr. Reshma L. Mahtani.