What Is Chronic Myelogenous Leukemia?
Leukemia is a type of cancer that starts in the blood or blood-forming tissues. There are many different types of leukemia, and treatment is different for each one. Chronic leukemias are slower growing than acute leukemias, but can be just as life threatening.
Chronic myelogenous leukemia is commonly referred to as CML. Other names for this type of cancer include chronic myeloid leukemia, chronic myelocytic leukemia, and chronic granulocytic leukemia.
This is a cancer of the white blood cells. In CML, blast cells, or immature white blood cells, form and multiply uncontrollably, they crowd out all the other types of necessary blood cells.
Progression of CML
CML has different phases of progression. Which phase the disease is in determines the appropriate treatment. The phases are based on the number of blast cells present and include: the chronic phase, the accelerated phase, and the blast crisis phase.
The Chronic Phase
This is the earliest stage of CML, and you may have some symptoms or none at all. During this phase, your white blood cells can still fight infections in your body.
The Accelerated Phase
In this phase, your red blood cell counts are low, and anemia (not enough iron in your blood) may occur. Platelet levels are also reduced, which may cause easy bruising or bleeding because platelets help to form blood clots. The amount of blast cells increases. A fairly common complication at this point is a swollen spleen, which may cause stomach pain.
The Blast Crisis Phase
A large number of blast cells are present in this advanced phase. Symptoms in this phase are more severe and can be life threatening.
What Causes CML?
CML is caused by a genetic mutation. Doctors do not know what causes the initial mutation.
In humans, there are 23 pairs of chromosomes. In individuals with CML, part of chromosome 9 is switched with a piece of chromosome 22 (Mayo Clinic, 2010). This makes a short chromosome 22 and a very long chromosome 9.
According to the Mayo Clinic, the short chromosome 22 is called the Philadelphia chromosome, and is present in 90 percent of CML patients (Mayo Clinic, 2010). Genes from chromosomes 9 and 22 then combine to form a gene, the BCR-ABL gene, that enables specific blood cells to multiply uncontrollably, causing CML.
How Is CML Diagnosed?
Because CML generally does not cause symptoms in its early stages, the cancer is often detected during a routine blood test. When there are symptoms, they are general and can be symptoms of other health conditions as well. Symptoms may include:
- night sweats
- swollen spleen
- feeling of fullness in the abdomen
If tests suggest that you may have cancer, a bone marrow biopsy is performed. This is to get a sample of bone marrow to send to a lab for analysis. A special needle with a tube will be inserted into either your hipbone or breastbone, and a small piece of bone marrow suctioned out.
Once diagnosed, tests will be done to explore the extent of disease in your body. A complete blood work-up is typically ordered, along with genetic tests done in a laboratory. Imaging tests such as an MRI, ultrasound, and CT scan can also be used to determine the extent of the disease.
How Is CML Treated?
There are multiple treatments for CML and your treatment may vary depending upon your health and the progression of the disease.
Targeted therapies are typically used first in CML treatment. These are drugs that attack a specific part of the cancer cell to kill it. In the case of CML, these drugs block the protein made by the BCR-ABL gene. They may include imatinib, dasatinib, or nilotinib. These are newer therapies that have been very successful.
Chemotherapy involves using drugs to kill cancer cells. These drugs are systemic, which means they travel through your entire body via your bloodstream. They can be given intravenously or orally, depending on the specific drug. They are a common cancer treatment with side effects that may be intense.
Bone Marrow Transplant
A bone marrow transplant (also called a blood stem cell transplant) is used when other treatments have failed. This is because the procedure is risky and there is a significant chance of adverse side effects. In this type of transplant, chemotherapy is used to kill the cancerous cells in your bone marrow before healthy donor cells are infused into your blood to replace them. Side effects of this procedure vary widely but can include minor things such as chills and flushing or major complications like anemia, infections, and cataracts.
Talk with your doctor about which treatment options are best for you and what side effects you can expect.