Definition

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

• Myeloblasts—a stem cell that evolves into specific types of white blood cells that help the body fight infection
• Red blood cells (RBCs)—carry oxygen
• Platelets—a blood component involved in clotting blood

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.

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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 cannot 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 people 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 chances of CML:

• 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—examination of a sample of blood, bone marrow, lymph node tissue, or cerebrospinal fluid
• Bone, blood marrow, lymph node tissue, or cerebrospinal fluid tests—to distinguish between types of leukemia
• Cytogenetic analysis—to look for DNA changes in the lymphocytes
• Immunophenotyping—examination of the proteins on cell surfaces and the antibodies produced by the body

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

• Chest x-ray
• CT scan
• MRI scan
• Ultrasound

Treatment

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

Prevention

There are no current guidelines to prevent CML because the cause is unknown.