What Are the Stages of Chronic Myeloid Leukemia?

To understand the best treatment options available to you for chronic myeloid leukemia (CML), it is important for you and your doctor to know the phase (stage) that the disease has reached.

Chronic phase - Patients in the chronic phase have stable disease with only minor symptoms. There is no cancer outside the bone marrow, blood, or spleen. White blood cell and platelet blood counts are easily controlled by a drug—called Gleevec^® (imatinib mesylate)—that targets the Philadelphia abnormality.

Accelerated phase - When chronic myeloid leukemia becomes difficult to control with imatinib, the white blood count begins to increase. New symptoms may appear and old symptoms may worsen. The spleen may enlarge and/or new abnormal chromosomes can be detected in the bone marrow cells. Eventually, the leukemia becomes completely resistant to treatment. The bone marrow becomes overburdened with large numbers of immature white blood cells known as "blasts." A diagnosis of accelerated phase requires at least one of the following:

• The persistent presence of 10 percent to 30 percent myeloblasts in the bone marrow or peripheral blood
• A major increase of the white blood cell count to more than 50,000, platelet counts that are increased or decreased, and red blood cell levels that are low despite treatment
• Progressive enlargement of the spleen
• Growth of leukemia outside the bone marrow or spleen
• The presence of any genetic abnormality in addition to a Philadelphia chromosome
• Persistent unexplained fever or bone pain
  

Blastic phase - Your disease is considered to be in blastic phase if you have 30 percent or more blasts in your marrow or blood.