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Chronic Myeloid Leukemia (CML)

Adult Chronic myelogenous leukemia (CML) is a type of cancer that occurs when the bone marrow produces excess amounts of white blood cells. Most cases occur in adults and risk increases with age.

CML is among a group of diseases that essentially cause an overactive bone marrow. The uncontrolled growth and accumulation of cells in patients with CML leads to a deficiency of red blood cells, blood-clotting platelets and normal infection-fighting white blood cells. When untreated, CML often turns into a form of acute leukemia.

Chronic Myeloid Leukemia Causes

While the actual cause of CML is unknown, it is distinguished from other types of leukemia by the presence of a genetic abnormality in white blood cells called the Philadelphia chromosome, a result of two genes, normally far apart in the cell, being placed next to each other. In rare cases, exposure to extremely high doses of radiation (most carefully studied in the Japanese survivors of the atomic bomb) and high dose radiation therapy from treatment of other cancers has been known to cause CML.

Chronic Myeloid Symptoms and Diagnosis

CML is often diagnosed during a routine physical examination that reveals an elevated white blood cell count. Symptoms of CML, which usually develop gradually, include:

  • Fatigue and shortness of breath
  • Infections and anemia
  • Bone pain and discomfort on the left side of the abdomen from an enlarged spleen
  • Excessive sweating, fever and intolerance for warm temperatures
  • Weight loss

Tests to determine the phase of the cancer are imperative to decide which treatment method to pursue. Diagnosis of CML is determined by the amount of unhealthy cells in the blood and bone marrow and is classified in three phases:

  • Chronic phase: The leukemic cell grows slowly; this phase lasts several years
  • Accelerated: Cancer cells begin growing faster
  • Blastic: Blastic phase turns into an acute type of leukemia and can be fatal

Chronic Myeloid Leukemia Treatment

The most effective way to treat CML Philadelphia chromosome is to significantly reduce or rid the patient’s body of the Philadelphia chromosome containing cells. Two different treatment methods are used in an attempt to accomplish this: oral medications and allogeneic (donor) stem cell transplantation.

Oral Medications

 

Oral drugs specifically engineered to target CML revolutionized the care of patients with CML.

A great majority of patients treated with this group of oral medication attain very good responses, have a much lower chance of accelerated or blast crisis CML and live longer. While the use of new drugs in the treatment of CML is very effective, we do not yet know for certain if it can cure the disease.

It is extremely important to monitor patients who take oral medications for CML very closely, as it is virtually impossible to know if the drugs are working properly based on how the patients feel or even with routine blood tests.

A newly diagnosed patient with chronic phase CML who is taking the drug must be constantly monitored. Types of monitoring include:

  • Frequent blood counts and blood tests during the first several weeks of therapy and every three months for the remainder of the course
  • Bone marrow biopsy after three months to determine the existence of the Philadelphia chromosome

 

Allogeneic Stem Cell Transplantation

Allogeneic stem cell transplantation can cure 60-80 percent of patients in the chronic phase, but is not without risk. It is very important to discuss the possibility of stem cell transplantation for almost all patients who have CML. Allogeneic transplants are generally used as the next line of therapy for patients with more advanced forms of CML. These are patients in accelerated or blast phase, or who cannot tolerate the drugs.

If CML is not adequately controlled on the medications, referral to a large experienced blood cancer treatment and stem cell transplant center is necessary.

The physicians at Colorado Blood Cancer Institute (CBCI) are the region’s specialists in the care of patients with CML.