Thomas Jefferson University

Chronic Myelogenous (CML)

Quick Facts

Chronic myelogenous leukemia is a disease in which the bone marrow makes too many white blood cells. Most people with CML have a gene mutation (change) called the Philadelphia chromosome.


Chronic myelogenous leukemia (also called CML or chronic granulocytic leukemia) is a slowly progressing blood and bone marrow disease that usually occurs during or after middle age, and rarely occurs in children.  In CML, too many blood stem cells develop into a type of white blood cell called granulocytes. These granulocytes are abnormal and do not become healthy white blood cells. They may also be called leukemic cells. The leukemic cells can build up in the blood and bone marrow so there is less room for healthy white blood cells, red blood cells, and platelets. When this happens, infection, anemia, or easy bleeding may occur. The prognosis (chance of recovery) and treatment options depend on the patient’s age, phase of CML, the amount of blasts in the blood or bone marrow, the size of the spleen at diagnosis, and the patient’s general health. Chronic myelogenous leukemia has 3 phases.

Specialized Physicians:
S. OnderAlpdogan, MD *
Atrayee Basu Mallick, MD
Avnish Bhatia, MD
Christina Brus, MD
Andrew E. Chapman, DO, FACP
Joanne E. Filicko-O'Hara, MD *
Neal Flomenberg, MD *
Margaret T. Kasner, MD *
Michael J. Ramirez
Lewis J. Rose, MD, FACP
John Wagner, MD *
Allison Zibelli, MD, FACP

*Practice Focus: Hematologic Malignancies

For further information contact:
Thomas Jefferson University Hospital

Chronic Phase:  In chronic phase CML, fewer than 10% of the cells in the blood and bone marrow are blast cells.

Accelerated Phase: In accelerated phase CML, 10% to 19% of the cells in the blood and bone marrow are blast cells.

Blastic Phase: In blastic phase CML, 20% or more of the cells in the blood or bone marrow are blast cells. When tiredness, fever, and an enlarged spleen occur during the blastic phase, it is called blast crisis.


There are different types of treatment for patients with chronic myelogenous leukemia.

Six types of standard treatment are used including targeted therapy, chemotherapy, biologic therapy, high-dose chemotherapy with stem cell transplant, donor lymphocyte infusion (DLI), and/o surgery.
Reference: National Cancer Institute.