Chronic Myelogenous Leukemia

What is chronic myelogenous leukemia?

Chronic myelogenous leukemia (CML) is a cancer of the blood and bone marrow. It affects a type of white blood cells called myelocytes. The cancer causes large numbers of abnormal white cells to form, crowding out other, normal blood cells needed by the body.

Other names for this type of leukemia are chronic myeloid leukemia and chronic granulocytic leukemia.

How does it occur?

The cancer starts in the bone marrow. Marrow is the soft, fatty tissue inside the hard, outer part of the bones. The marrow makes blood stem cells, which become the different types of blood cells, including white blood cells, red blood cells, and platelets.

Normally, white blood cells help your body fight infection and other diseases. Chronic myelogenous leukemia happens when the body makes too many abnormal white blood cells. The abnormal cells crowd out other, normal blood cells needed by the body. The abnormal white blood cells cannot fight infections as well as normal white blood cells. In addition, you may become anemic because you don’t have enough red blood cells.

Most people who have CML have an abnormal chromosome called the Philadelphia chromosome. Chromosomes contain the genetic material that determines how cells look and act. The problem is that 2 chromosomes have swapped sections and a new gene has been created on the Philadelphia chromosome. The new gene makes a protein called tyrosine kinase. This protein causes abnormal white blood cells to grow out of control.

Usually it is not known why this chromosome change happens. The Philadelphia chromosome is not passed from parent to child, so CML does not appear to be an inherited problem. However, your risk of CML is greater if:

• You are middle aged or older.
• You have been exposed to a very high dose of radiation, like from an atomic bomb blast.

What are the symptoms?

CML may have no symptoms or just mild symptoms at first. The symptoms slowly get worse. They may include:

• feeling very tired
• unexpected weight loss
• sweating at night
• fever
• a sense of fullness or pain below the ribs on the left side, caused by an enlarged spleen
• feeling full after eating less than a full meal.

How is it diagnosed?

Your healthcare provider may discover the disease during a routine blood test. Or your provider may find that you have an enlarged spleen during a physical exam.

A sample of your bone marrow will be taken. In this procedure called a biopsy, a small sample of bone marrow is taken from the hipbone in back and examined under a microscope. Your healthcare provider will get the sample by first numbing the area over the bone. Then a needle will be inserted to suction the sample into a syringe. Usually the biopsy can be done in your provider's office.

A sample of your blood or bone marrow can be tested in the lab to look for the Philadelphia chromosome.

How is it treated?

CML can be treated with a class of drugs called targeted agents. The targeted agent usually given is imatinib. The goal is to give you a normal blood count by blocking the protein tyrosine kinase and stopping it from causing stem cells to develop into more white blood cells than the body needs. This drug can be effective for years. However, after a while it almost always stops working. When the disease no longer responds to imatinib, similar drugs (dasatinib or nilotinib) are usually effective, at least for a while. These drugs do not cure the disease.

You will need to take medicine regularly to keep your white blood cell count normal, or you may need medicine only part of the time. Your healthcare provider will watch your condition and your blood cell count closely. You will have blood tests to make sure the medicine is working.

If other treatments aren’t working, a stem cell transplant may be a possible treatment. First, high doses of chemotherapy drugs are given to destroy blood-forming cells. Then, the cells are replaced with healthy stem cells taken from a compatible donor's blood or bone marrow. Although the cure rate is 40 to 50%, this treatment is very difficult. Sometimes the transplant is not successful. In rare cases it can be fatal.

How long will the effects last?

With treatment, many people with CML have no symptoms from the disease. The time when symptoms go away is called a remission. You may live a relatively normal life for many years.

How can I take care of myself?

• Make sure that you have regular checkups and follow your provider's advice for taking care of yourself. Discuss questions and concerns with your provider.
• Know your medicines and take them exactly as your provider tells you to. Know what they look like, how much you are to take each time, how often you are to take them, and why you take each one.
• Check with your healthcare provider before taking other medicines, including nonprescription products or other forms of treatment. Carry a list of your medicines in your wallet or purse. Include any nonprescription medicines and supplements on the list.
• Eat a healthy diet and be as active as is comfortable and recommended. Ask your provider if you need to avoid some activities or be careful about what you eat. Get plenty of rest.
• Take precautions during your treatment to avoid infections. Try to stay away from crowds and people who may be sick. Avoid small children, especially children who attend day care (they often have colds and other infections). When you are around people, including family, wash your hands often. Do not share towels. Ask your provider if you should wear a surgical mask when you are out in public so that you are less likely to breathe in germs.
• If you lose your appetite and begin to lose weight, ask your provider about medicine that can help you have a better appetite.
• Do not smoke.
• Ask your provider if you need to avoid drinking alcohol. It may interfere with medicines you are taking. Alcohol can also make it harder for white blood cells to fight infections.
• Make sure you get a pneumonia shot and yearly flu shots.
• Learn about your illness. Join a support group to learn from other cancer survivors and to share what has helped you.
• Tell your healthcare provider if you have new or worsening:
  • tiredness
  • weakness
  • fever
  • sore throat
  • easy bruising or bleeding
  • loss of appetite
  • weight loss
  • bone pain
  • feeling of fullness below the ribs, especially on the left
  • swollen lymph nodes in the neck, underarms, and groin
  • sweating at night
  • infections
• For more information, contact the Leukemia and Lymphoma Society at 800-955-4572 or visit their Web site at http://www.leukemia.org.

How can I help prevent chronic myelogenous leukemia?

The cause of CML is not well understood, and no risk factors have been found, so doctors don’t know how to prevent it.