Chronic myelogenous leukemia (CML)

Definition

Chronic myelogenous leukemia is cancer that starts inside bone marrow, the soft tissue inside bones that helps form blood cells.

CML is one of many types of leukemia. See also:

• Acute myeloid leukemia (AML)
• Chronic lymphocytic leukemia (CLL)
• Leukemia

Alternative Names

CML; Chronic granulocytic leukemia; Leukemia - chronic granulocytic

Causes, incidence, and risk factors

CML is the rapid growth of immature cells that make a certain type of white blood cell. Such cells are found in the bone marrow, blood, and other body tissues.

CML most often occurs in middle-aged adults and in children.

It is usually associated with an abnormal chromosome called the Philadelphia chromosome.

Radiation exposure can increase your risk of developing CML. You may be exposed to radiation from:

• Radiation treatments used in the past to treat thyroid cancer or Hodgkin’s lymphoma
• Nuclear disaster

It takes many years to develop leukemia from radiation exposure. Most people treated for cancer with radiation do not develop leukemia. Most patients with CML have not been exposed to radiation.

Symptoms

Chronic myelogenous leukemia is grouped into several phases:

• Chronic
• Accelerated
• Blast crisis

The chronic phase can last for months or years. The disease may have few or no symptoms during this time. Most people are diagnosed during this stage, when they are having blood tests done for other reasons.

The accelerated phase is a more dangerous phase. Leukemia cells grow more quickly. Common symptoms include fever (without infection), bone pain, and a swollen spleen.

Untreated CML leads to the blast crisis phase. Bleeding and infection may occur due to bone marrow failure.

Other possible symptoms of a blast crisis include:

• Bruising
• Excessive sweating (night sweats)
• Fatigue
• Fever
• Pressure under the lower left ribs from a swollen spleen
• Rash - small pinpoint red marks on the skin (petechiae)
• Weakness

Signs and tests

A physical examination often reveals a swollen spleen. A complete blood count (CBC) shows an increased number of white blood cells.

Other tests include:

• Bone marrow biopsy
• Blood and bone marrow testing for the presence of the Philadelphia chromosome
• Platelet count

Treatment

A medicine called Imatinib (Gleevec) is the first treatment for nearly everyone with CML. Gleevec is a pill, taken by mouth. New medications similar to Gleevec include dasatinib (Sprycel) and nilotinib (Tasigna

Sometimes a chemotherapy medicine called hydroxyurea (Hydrea) is used temporarily to reduce the white blood cell count if it is very high at diagnosis.

The blast crisis phase is very difficult to treat, because there is a very high count of immature white blood cells (leukemia cells). It is treated similarly to acute myeloid leukemia (AML) or acute lymphoid leukemia (ALL).

The only known cure for CML is a bone marrow transplant or stem cell transplant. You should discuss your options in detail with your oncologist.

You and your healthcare provider may need to manage many other issues or concerns during your leukemia treatment. See also:

• Being at home during chemotherapy
• Manging your pets during chemotherapy
• Bleeding problems
• Eating enough calories when you're sick
• Swelling and pain in your mouth
• Safe eating during cancer treatment

Support Groups

See:

• Cancer support group
• Leukemia support group

Expectations (prognosis)

Since the introduction of Gleevec, the outlook for patients with CML has improved dramatically. When the signs and symptoms of CML go away, you are said to be in remission. Many patients can remain in remission for many years while on this drug.

Stem cell tansplantation is usually considered in patients whose disease comes back after taking imatinib (Gleevec).

Complications

Blast crisis can lead to complications, including infection, bleeding, fatigue, unexplained fever, and kidney problems. Chemotherapy can have serious side effects, depending on the drugs used.

Calling your health care provider

Prevention

Avoid exposure to radiation when possible.

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References

Kantarjian H, O'Brien S. The chronic leukemias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 190.

National Comprehensive Cancer Network. National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology: Chronic Myelogenous Leukemia. 2011. Version 2.2011.