What is Chronic Myelocytic Leukemia: Causes, Risk Factors, Symptoms, and Treatment Options

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What is Chronic Myelocytic Leukemia?

There are different types of leukemia; however, CML differs from acute leukemias in that they produce an increasing amount of, what appear to be, normal-seeming WBCs. Leukemia cells in this form of leukemia are produced not only in the bone marrow, but also in the liver and spleen.[1]

Causes and Risk Factors

Chronic myelocytic leukemia is caused by two chromosomes forming another known as the Philadelphia (Ph) chromosome. The Ph chromosome is responsible for producing tyrosine kinase, which is to blame for atypical WBC growth.

Risk factors associated with CML include a history of radiation exposure and being a male of older age, although this disease is not partial.[2] CML can affect both men and women over the age of 10, particularly those between 40 and 60 years of age.[3]

Signs and Symptoms

Patients generally remain asymptomatic in its earliest stage. As the disease advances, however, it accelerates to what is known as “blast crisis.” In this phase, mature WBCs are no longer being produced, the spleen becomes vastly enlarged, and the patient generally experiences various signs and symptoms, some of which include:

  • Night sweats
  • Fatigue
  • Physically weak
  • Bruises easily
  • Paleness
  • Fever
  • Loss of appetite

Various Treatment Options

There is no cure for chronic myelocytic leukemia, per se; however, there are treatment options available that will assist with slowing the progress of this disease. Common treatments include targeted anti-cancer drugs, chemotherapy, radiation therapy and bone marrow transplant.

Drugs such as imatinib, dasatinib and nilotinib are known as tyrosine kinase inhibitors. These work by blocking tyrosine kinase, the enzyme responsible for overturning abnormal WBCs. These medications are not without their own side effects, including muscle cramps, diarrhea and fatigue. Patients generally remain on these drugs for an undetermined amount of time.

Chemotherapy is often used in conjunction with other treatment methods by killing cancer cells through the bloodstream. This therapy may be taken orally, intravenously, intramuscularly or through intrathecal chemotherapy.

Radiation therapy is a treatment used to relieve patients’ symptoms by reducing tumors and killing cancer cells through an external machine emitting radiation.

Generally, as a last resort, patients may undergo a bone marrow transplant. It is the only potential cure for relatively healthy candidates. This procedure carries with it its own list of complications so it is used for those that have not experienced benefit from any other therapy. High doses of chemotherapy are targeted at the cells within the bone marrow during the procedure. Healthy bone marrow from the patient or donor is then introduced into the bloodstream with the hope that the cancer cells will be overridden with healthy ones.


The information provided herein is provided for educational purposes only. Patients with any of the above symptoms, questions, or concerns should seek the help and advice of their health care provider.


1. Merck Manuals website. Chronic Myelocytic Leukemia (CML). Accessed December 17, 2010.[1,2]

2. Mayo Clinic website. Chronic myelogenous leukemia: Risk factors. Accessed December 17, 2010.

3. MedicineNet website. Chronic myelogenous leukemia. Accessed December 17, 2010.