Leukemia Treatment Chronic Myelogenous

Chronic myelogenous leukemia (CML) is a cancer of the bone marrow that initially develops slowly, but accelerates over time.

CML occurs due to a chromosomal translocation in which part of chromosome 9 switches places with chromosome 22. This translocation results in the Philadelphia chromosome, triggering excessive production of white blood cells.

Stages of Chronic Myelogenous Leukemia

Chronic myelogenous leukemia treatment depends on the disease’s stage at the time of diagnosis. CML has three distinct phases:

  • Chronic CML: White blood cell levels build up slowly for two to five years, often without noticeable symptoms.
  • Accelerated CML: Immature white blood cells called blasts accumulate in the blood, bone marrow, spleen and liver. Weight loss, anemia, night sweats, fever and other symptoms of CML begin to appear.
  • Blast phase/Blast crisis: Immature blast cells accumulate rapidly, out-populating healthy blood cells. During this phase, CML resembles acute types of leukemia.

Most cases of chronic myelogenous leukemia are diagnosed during the chronic phase. Treatment of CML becomes less effective as the disease progresses from early to later phases.

Imatinib Therapy

Imatinib therapy is the initial treatment for most cases of CML. Imatinib is a targeted therapy known as a kinase inhibitor. Kinase inhibitors block the action of a protein produced by CML cells called tyrosine kinase. By blocking tyrosine kinase, imatinib therapy prevents leukemia cells from replicating and multiplying.

Imatinib therapy is a relatively new treatment, so the long-term success and effects of the targeted therapy have yet to be fully determined. However, up to 80 percent of CML cases treated with imatinib therapy are stable after five years. Because chronic myelogenous leukemia cells can’t be completely eradicated with imatinib therapy, ongoing treatment is recommended.

Patients who don’t respond to imatinib therapy may receive other targeted medications, including dastinib and nilotinib. Treatment with imatinib therapy or similar medication works best in cases of chronic myelogenous leukemia diagnosed in the chronic phase.

Bone Marrow/Cord Blood Transplantation

Imatinib therapy doesn’t work for every case of CML, particularly in the accelerated or blast phases. In such cases, a stem cell transplant may be suggested. A bone marrow transplant or umbilical cord blood transplantation, if successful, can cure chronic myelogenous leukemia. In contrast, imatinib therapy only keeps the disease in check.

Stem cell transplants are, however, complex procedures with potentially serious complications. As a result, the procedure tends to be reserved for patients who don’t respond to other treatments. Prognosis depends on the disease phase: While 20 to 40 percent of people with accelerated CML may live for years after a bone marrow transplant, long-term survival for stem cell transplants performed during the blast crisis is only 10 percent.

Interferon Therapy and Chronic Myelogenous Leukemia

Interferon therapy uses a synthetic form of an immune system cell to combat chronic myelogenous leukemia. Interferon therapy strengthens the body’s immune system, with the goal of stimulating it to attack cancer cells and reducing the growth of leukemia cells.

Interferon therapy isn’t often offered for chronic myelogenous leukemia, but may be an option if other treatments fail or can’t be used (such as during pregnancy).

Resources

American Cancer Society. (2009). Treatment of chronic myeloid leukemia by phase. Retrieved April 2, 2010, from http://www.cancer.org/docroot/CRI/content/CRI_2_4_4x_Treatment_of_Chronic_Myeloid_Leukemia_by_Phase_CML.asp.

Mayo Clinic. (2008). Chronic myelogenous leukemia. Retrieved April 2, 2010, from http://www.mayoclinic.com/health/chronic-myelogenous-leukemia/DS00564/DSECTION=treatments-and-drugs.

National Cancer Institute. (2009). Chronic myelogenous leukemia treatment (PDQ): Treatment option overview. Retrieved April 2, 2010, from http://www.cancer.gov/cancertopics/pdq/treatment/CML/Patient/page4.

National Marrow Donor Program. (n.d.). Chronic myelogenous leukemia (CML), imatinib (gleevec) and transplant. Retrieved April 2, 2010, from http://www.marrow.org/PATIENT/Undrstnd_Disease_Treat/Lrn_about_Disease/CML/index.html.