Chronic myelogenous leukemia (CML)
Chronic myelogenous leukemia (CML) is cancer that starts inside bone marrow. This is the soft tissue in the center of bones that helps form all blood cells.
CML causes an uncontrolled growth of immature cells that make a certain type of white blood cell called myeloid cells. The diseased cells build up in the bone marrow and blood.
CML; Chronic myeloid leukemia; Chronic granulocytic leukemia; Leukemia - chronic granulocytic
Causes, incidence, and risk factors
Cause of CML is often related to an abnormal chromosome called the Philadelphia chromosome.
Radiation exposure can increase the risk of developing CML. Radiation exposure can be from radiation treatments used in the past to treat thyroid cancer or Hodgkin lymphoma or from a 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.
CML most often occurs in middle-age adults and in children.
Chronic myelogenous leukemia is grouped into several phases:
- 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 have blood tests done for other reasons.
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:
- Excessive sweating (night sweats)
- Pressure under the lower left ribs from a swollen spleen
- Rash - small pinpoint red marks on the skin (petechiae)
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
Medicine called imatinib (Gleevec) is the first treatment for nearly everyone with CML. Gleevec is a pill, taken by mouth. It targets the abnormal protein made by the Philadelphia chromosome. Other medicines similar to Gleevec may be used.
Sometimes chemotherapy is used to reduce the white blood cell count if it is very high at diagnosis.
The blast crisis phase is very difficult to treat. This is because there is a very high count of immature white blood cells (leukemia cells).
The only known cure for CML is a bone marrow transplant, or stem cell transplant. Most patients, though, do not need a transplant because medicines, such as Gleevec, are successful in treating CML. Discuss your options with your oncologist.
You and your healthcare provider may need to manage many other issues or concerns during your leukemia treatment, including:
- Being at home during chemotherapy
- Managing your pets during chemotherapy
- Bleeding problems
- Eating enough calories when you are sick
- Swelling and pain in your mouth
- Safe eating during cancer treatment
You can ease the stress of illness by joining a cancer support group. Sharing with others who have common experiences and problems can help you not feel alone.
Taking Gleevec improves the outlook for patients with CML. When the signs and symptoms of CML go away and blood counts and bone marrow biopsy appear normal, the person is considered in remission. Many persons can remain in remission for many years while on this medicine.
Stem cell tansplant is usually considered in persons whose disease comes back after taking Gleevec.
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.
Avoid exposure to radiation when possible.
Kantarjian H, Cortes J. Chronic myeloid leukemia. In: Abeloff MD, Armitage JO, Niederhuber JE, et al., eds. Abeloff’s Clinical Oncology. 4th ed. Philadelphia, PA: Elsevier Churchill-Livingstone; 2008:chap 107
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Chronic Myelogenous Leukemia. Version 4.2013. Available at http://www.nccn.org/professionals/physician_gls/pdf/cml.pdf. Accessed March 7, 2013.