Chronic myelogenous leukemia (CML)

Alternative names:

chronic granulocytic leukemia; chronic myelocytic leukemia

Definition:

A malignant cancer of the bone marrow that causes rapid growth of the blood forming cells, known as myeloid precursors, in the bone marrow; peripheral blood; and body tissues.

Causes, incidence, and risk factors:

The disease tends to occur in middle-aged people and is associated with a chromosome abnormality called the Philadelphia chromosome. Chronic myelogenous leukemia is characterized by a chronic phase, then a subsequent transformation to a more malignant blastic phase. The disease may remain stable in the chronic phase for years before becoming overtly malignant. Acceleration of the disease may be associated with fever without infection, bone pain, and an enlarged spleen. Within 5 years in most people, the disease progresses to a blast crisis, when there is a very high count of immature white blood cells. The blast phase of the leukemia is very difficult to treat. Bleeding and infection may occur because of bone marrow failure. Known risk factors are exposure to ionizing radiation and benzene.