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Chronic Myelogenous Leukemia (CML), Gleevec and Transplant

Chronic myelogenous leukemia (CML) is a slow-growing cancer of the white blood cells. It is also sometimes called chronic myeloid, chronic granulocytic or chronic myelocytic leukemia. CML is a common leukemia. In the United States, more than 20,000 people have CML and about 4,600 new cases are diagnosed each year. Most cases of CML appear in adults, but about 2 to 4% of CML patients are children.

CML patients have bone marrow that makes too many white blood cells. CML is caused by a change in the genetic code of some of the cells in the bone marrow. In these cells, part of chromosome 9 moves to chromosome 22. This creates an abnormal chromosome called the Philadelphia chromosome. The Philadelphia chromosome makes an enzyme (called tyrosine kinase) that signals the body to make too many white blood cells. Doctors do not know what causes the Philadelphia chromosome to appear.

Chronic myelogenous leukemia phases and symptoms

CML has three phases. Most patients are diagnosed in the first phase, called the chronic phase. It can develop over time into the second (accelerated) and third (blast) phase.

Chronic phase

In the chronic phase, there are more white blood cells in the blood and bone marrow than usual. Most are mature cells that can work normally. Depending on treatment, the chronic phase may last two to five years or more before turning into the accelerated phase. The symptoms of chronic phase CML depend on how high the person's white blood cell count is. Often, people do not notice any symptoms at all. Their CML is found during a routine doctor's visit. Others may have symptoms such as:

Fatigue (tiredness)
Headache
Pain or a feeling of fullness on the left side of the abdomen (caused by an enlarged spleen)

Accelerated phase

In the accelerated phase, there are more blasts (immature white blood cells) in the marrow, blood, liver and spleen. The blasts cannot fight infections the way normal white blood cells do. This phase may last one to three months before reaching the blast phase. Symptoms are more noticeable than in chronic phase. In addition to the symptoms above, symptoms can include:

Fever
Night sweats
Weight loss
Shortness of breath and pale skin caused by anemia (too few red blood cells)

Blast phase

In the blast phase, the number of blasts in the bloodstream grow rapidly. As a result, there are fewer normal blood cells (white blood cells, red blood cells and platelets), and the symptoms listed above become severe. Patients often have problems with bruises, bleeding and infection. The blast phase is similar to acute myelogenous leukemia.

Chronic myelogenous leukemia treatments

Treatment options for CML include:

Gleevec
A marrow or peripheral (circulating) blood cell transplant
Interferon, often along with cytarabine
Hydroxyurea

The choice of treatments is based on a patient's age, overall health and related factors. The anti-cancer drugs interferon, cytarabine and hydroxyurea were the main CML treatments before Gleevec was available. They are still recommended for some patients. The two treatments more often considered today — Gleevec or a transplant — are discussed below.

Gleevec

For most patients, a drug called Gleevec is the standard first treatment. (Gleevec is also known as imatinib mesylate.) Gleevec was approved by the U.S. Food and Drug Administration (FDA) in 2001. Gleevec blocks the tyrosine kinase enzyme so that the body stops (or slows down) making too many white blood cells.

Most patients' disease responds to Gleevec. Because it is a newer treatment, doctors still have questions about whether patients' response to Gleevec will last for a long time. To learn about how doctors measure the response to Gleevec, clinical trials results and questions about Gleevec, see Gleevec Treatment for CML.

Marrow or peripheral blood cell transplant

A marrow or peripheral blood cell transplant (also called a BMT) using cells from a family member or unrelated donor (an allogeneic transplant) is the only known treatment that can cure CML, but it has risks and is not an option for all patients. A transplant replaces the abnormal cells in the patient's bone marrow with healthy cells from a donor. For details about the transplant process, see Learning about Bone Marrow or Cord Blood Transplants.

A transplant is not an option for all patients, because:

Some patients are not strong or healthy enough to tolerate the high doses of chemotherapy and/or radiation used before a transplant. A newer approach, called a reduced-intensity transplant may be an option for some of these patients.
Some patients do not have a suitable donor to use for transplant.

Even for patients in good health (other than their CML), a transplant has risks of life-threatening complications. If transplant is an option for you, your doctor can talk with you about your risks and your chances of a cure with transplant. For statistics showing patients' results after transplant, see CML transplant survival outcomes data.

Autologous transplant

Autologous transplant (using the patient's own cells) is being studied as a treatment for CML that returns after Gleevec treatment [1]. Patients who show no sign of disease after treatment with Gleevec can have some of their blood-forming cells collected and frozen. These cells can then be returned to the patient if the disease returns. Because this is a newer treatment for CML, there is no long-term data showing how well it works.

Making treatment choices

For patients with CML in chronic phase, there are better treatment options today than in the past. Even so, doctors have many questions about the best treatment.

Gleevec helps many patients and has few serious side effects, so it is the standard first treatment for most patients. However, it is too soon to know how well it will work over the long term.
A transplant may cure CML, but it has serious risks. It is not an option for all patients.

The best treatment will be different for different patients, depending on a patient's age and other health factors. Research into treatment for CML is ongoing, and recommended treatments can change quickly. It is important to talk with your doctor about your treatment options.

Even if you begin treatment with Gleevec, it can be a good idea to plan for the possibility of a future transplant. Your doctor can take steps to be prepared if Gleevec does not give you good results or if Gleevec stops working over time. Your doctor can check whether you have any possible donors in your family. He or she can also search the National Marrow Donor Program Registry for potential unrelated donors. That way, if you and your doctor decide you need a transplant later, the first steps of the donor search will be done and you may be able to move to transplant more quickly.

Information to share with your doctor

The Physician Resources section of this Web site includes information for doctors about timing and outcomes of transplants for CML, as well as references to related medical journal articles. You may want to share some of this information with your doctor.

References

Bhatia R, McGlave PB. Autologous hematopoietic cell transplantation for chronic myelogenous leukemia. Hematol Oncol Clin North Am. 2004; 18(3):715-732, xi. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?
cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15271402