Definition
Chronic myelogenous leukemia (CML) is a cancer of the blood and bone marrow. The bone marrow makes abnormal blood cells including:
- Myeloblasts—a type of white blood cell, fights infection
- Red blood cells (RBCs)—carry oxygen
- Platelets—makes blood clot, stops bleeding in cuts or bruises
CML progresses gradually. It is often slow growing for many years. Over time, it may change into acute myelogenous leukemia (AML). This is a more aggressive type of leukemia. It progresses more rapidly and is more serious.
Cancer occurs when cells in the body become abnormal. They divide without control or order. Leukemia is cancer of the white blood cells and their parent cells. Leukemia cells do not function normally. They cannot do what normal blood cells do. In this case, they can not fight infections. This means that the person is more likely to become infected with viruses or bacteria. The cancerous cells also overgrow the bone marrow. This forces other normal cells, like platelets out. Platelets are needed to help the blood clot. As a result, people with leukemia may bleed more easily.
Causes
CML is almost always associated with a gene mutation. The gene is in a chromosome called the Philadelphia chromosome. This mutation occurs during life. It is not passed from parent to child. In most cases, the cause of the mutation is not known. Studies show that exposure to large doses of radiation is associated with development of CML. It may be found in survivors of nuclear accidents or of atomic bomb blasts. However, most patients with the condition have not been exposed to radiation.
Risk Factors
The following factors increase your chance of developing CML:
- Sex: male
- Increased age
- Exposure to atomic bomb radiation
- Exposure to nuclear reactor accident
- Smoking is the only lifestyle factor that has been linked to leukemia. Its association with CML is still unclear.
Symptoms
These symptoms may also be caused by other, less serious health conditions.
- Tiredness
- Lack of energy
- Fatigue
- Unexplained weight loss
- Night sweats
- Fever
- Pain or a feeling of fullness below the ribs
- Bone pain
- Joint pain
- Reduced exercise tolerance
- Enlargement of the liver or spleen
- Unexplained bleeding or unusual bruising
Diagnosis
Your doctor will ask about your symptoms and medical history. A physical exam will be done. Your liver and spleen will be examined for swelling. The doctor will also look for swelling in lymph nodes in the armpits, groin, or neck. You will likely be referred to an oncologist. This is a doctor who focuses on treating cancer.
- Your bodily fluids and tissue may be tested. This can be done with:
- Blood tests
- Bone marrow aspiration
- Bone marrow biopsy
- Routine microscopic exam
- Bone, blood marrow, lymph node tissue, or cerebrospinal fluid tests
- Cytogenetic analysis
- Your doctor may need pictures of your bodily structures. This can be done with:
- Chest x-ray
- CT scan
- MRI scan
- Ultrasound
Treatment
Talk with your doctor about the best plan for you. Treatment options include:
Targeted Drug Therapy
Targeted drug therapy inhibits the molecule that triggers the development of leukemia and the gene that is associated with it. This medication is often used in early stages of CML.
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells. It may be given by pill, injection, or via a catheter. The drugs enter the bloodstream and travel through the body. While this will focus on cancer cells, some healthy cells are also killed.
High-dose Chemotherapy With Stem Cell Transplant
High doses of chemotherapy are followed by a transplant of stem cells (immature blood cells). These will replace blood-forming cells destroyed by cancer treatment. Stem cells are removed from the blood or bone marrow of the patient or donor. They are then infused into the patient.
Donor Lymphocyte Infusion
Lymphocytes are a type of white blood cell. A donor’s cells are infused into the patient. The cancer cells do not recognize these cells. They do not attack them.
Surgery
A splenectomy is a surgery to remove the spleen. It may be done if the spleen has become enlarged from the leukemia. It may also be done if other complications develop.
Prevention
There are no guidelines for preventing CML. It is possible that smoking is associated with CML. You may reduce your risk by not smoking.