Health Library

Chronic Myelocytic Leukemia

Definition

Chronic myelogenous leukemia (CML) is a cancer of the blood and bone marrow. Under normal circumstances, the bone marrow makes:

  • Myeloblasts—a type of white blood cell that fights infection
  • Red blood cells (RBCs)—carries oxygen to the body's cells and tissues
  • Platelets—makes blood clot to stop bleeding in cuts or bruises

CML progresses gradually. It is often slow growing for many years. Over time, it may change into acute myelogenous leukemia (AML). This is a more aggressive type of leukemia. It progresses more rapidly and is more serious.

White Blood Cells
White Blood Cells
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Causes

Cancer occurs when cells in the body become abnormal. They divide without control or order. Leukemia is cancer of the white blood cells and their parent cells. Leukemia cells do not function normally. In this case, they can not fight infections. This means that the person is more likely to become infected with viruses or bacteria. The cancerous cells also overgrow the bone marrow. This forces other normal cells, like platelets out. Platelets are needed to help the blood clot. As a result, people with leukemia may bleed more easily.

CML is almost always associated with a gene mutation. The gene is in a chromosome called the Philadelphia chromosome. This mutation occurs during life. It is not passed from parent to child. In most cases, the cause of the mutation is not known. Studies show that exposure to large doses of radiation is associated with development of CML. It may be found in survivors of nuclear accidents or of atomic bomb blasts. However, most patients with the condition have not been exposed to radiation.

Risk Factors

CML is more common in men and in those of increasing age. Other factors that may increase your chance of CML include:

  • Smoking is the only lifestyle factor that has been linked to leukemia. Its association with CML is still unclear.
  • Exposure to atomic bomb radiation
  • Exposure to nuclear reactor accident

Symptoms

CML may cause:

  • Tiredness
  • Lack of energy
  • Fatigue
  • Unexplained weight loss
  • Night sweats
  • Fever
  • Pain or a feeling of fullness below the ribs
  • Bone pain
  • Joint pain
  • Reduced exercise tolerance
  • Enlargement of the liver or spleen
  • Unexplained bleeding or unusual bruising

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done. Your liver and spleen will be examined for swelling. The doctor will also look for swelling in lymph nodes in the armpits, groin, or neck.

Tests may include:

  • Blood tests
  • Bone marrow biopsy
  • Routine microscopic exam
  • Bone, blood marrow, lymph node tissue, or cerebrospinal fluid tests
  • Cytogenetic analysis

Imaging tests can evaluate other bodily structures. These can be done with:

Treatment

Talk with your doctor about the best plan for you. Treatment options include:

Targeted Drug Therapy

Targeted drug therapy inhibits the molecule that triggers the development of leukemia and the gene that is associated with it. This medication is often used in early stages of CML.

Chemotherapy

Chemotherapy is the use of drugs to kill cancer cells. It may be given by pill, injection, or via a catheter. The drugs enter the bloodstream and travel through the body. While this will focus on cancer cells, some healthy cells are also killed.

High-dose Chemotherapy With Stem Cell Transplant

High doses of chemotherapy are followed by a transplant of stem cells (immature blood cells). These will replace blood-forming cells destroyed by cancer treatment. Stem cells are removed from the blood or bone marrow of the patient or donor. They are then infused into the patient.

Donor Lymphocyte Infusion

Lymphocytes are a type of white blood cell. A donor’s cells are infused into the patient. The cancer cells do not recognize these cells. They do not attack them.

Surgery

A splenectomy is a surgery to remove the spleen. It may be done if the spleen has become enlarged from the leukemia. It may also be done if other complications develop.

Prevention

There are no guidelines for preventing CML. It is possible that smoking is associated with CML. You may reduce your risk by not smoking.

Resources

American Cancer Society
http://www.cancer.org

The Leukemia and Lymphoma Society
http://www.leukemia-lymphoma.org

Canadian Resources

BC Cancer Agency
http://www.bccancer.bc.ca

Canadian Cancer Society
http://www.cancer.ca

References

Chronic myelogenous leukemia (PDQ): treatment. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/pdq/treatment/CML/Patient. Accessed January 29, 2013.

Chronic myeloid leukemia. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated December 17, 2012. Accessed January 29, 2013.

Leukemia—chronic myeloid (CML). American Cancer Society website. Available at: http://www.cancer.org/acs/groups/cid/documents/webcontent/003112-pdf.pdf. Accessed January 29, 2013.