Leukemia strikes early blood-forming cells, usually the white blood cells, but sometimes it occurs in other types of blood cells. According to the American Cancer Society’s 2018 estimated statistics, there will be about 60,300 new cases of leukemia in the United States in 2018, and about 24,370 deaths will result from this disease. There are several different types of leukemia, such as Acute Lymphocytic Leukemia, Acute Myeloid Leukemia, Chronic Lymphocytic Leukemia, and Chronic Myeloid Leukemia. Each type has its own risk factors, symptoms, and treatment options.
Chronic Myeloid Leukemia (CML)
CML occurs when a genetic change happens in the early-forming cells that make red-blood cells, platelets, and most types of white-blood cells (but not lymphocytes). CML is slow growing, but it can change into a fast growing leukemia, becoming hard to treat. The American Cancer Society estimates that 8,430 people (average age of 64) will be diagnosed with CML in 2018, and 1,090 people will die from it.
Causes of Chronic Myeloid Leukemia
Most cases of CML occur when chromosomes 9 and 22 switch during cell division, making chromosome 22 too short. This abnormal chromosome is known as the Philadelphia chromosome and is found in the leukemia cells of nearly all CML patients. The switching of these chromosomes also forms a new gene that creates a protein which causes the CML cells to grow and reproduce. The known risk factors include
- Gender (higher in males)
- Radiation exposure
- Age (increases with age)
Symptoms of Chronic Myeloid Leukemia
The symptoms of CML are more often caused by other things. These are some of the same symptoms seen in other leukemias. These symptoms include the following:
- Weight loss
- Loss of appetite
- Shortness of breath
- Fever and Night sweats
- Bone pain
- Enlarged spleen (mass under the left side of the rib cage)
- Early Satiety (Feeling full after eating a small amount of food)
- Persistent infections
- Easy Bruising, Gum Bleeding or frequent nosebleeds
Diagnosis of Chronic Myeloid Leukemia
Most people do not have symptoms for a long time, so diagnosis usually occurs during routine checkups or when blood tests are ordered for an unrelated health problem. Further steps include:
- Medical history
- Physical exam
- Blood tests including blood counts and blood smear
- Bone marrow aspiration and biopsy
- Lymph node biopsy
- Chromosome testing
- Lumbar puncture (spinal tap)
- Imaging tests including X-rays, CT scan and Bone scan
Staging of Chronic Myeloid Leukemia
CML is not staged like most cancers. Instead, depending on factors such as blood counts, the age of the patient, and whether the spleen is enlarged, CML will be classified into the following phases:
- Chronic phase (most common phase of diagnosis): Less than 10% immature white blood cells (blasts). Symptoms, if present, are fairly mild, and most patients respond to treatment.
- Accelerated phase: This is characterized by certain abnormalities on the blood tests. There are between 10-20% blasts or high blood basophil count (at least 20% of white blood cells) or abnormally high or low platelet count. There may be new chromosome changes in the leukemia cells. Patients may have fever, poor appetite, and weight loss. Treatment is not as effective as in the chronic phase.
- Acute phase or Blast phase: This is characterized by certain abnormalities on the blood tests. More than 20% blasts, which have often spread to organs beyond the bone marrow. These patients also have similar symptoms as seen in accelerate phase such fever, poor appetite and weight loss. In this phase, CML becomes much more aggressive.
Treatment of Chronic Myeloid Leukemia
The most common treatment for CML is targeted therapy drugs. Possible additional treatments include:
Prevention of Chronic Myeloid Leukemia
There is no known way to prevent CML.