Chronic Myelogenous Leukemia

Chronic myelogenous leukemia, which is also called CML, is a kind of cancer that occurs in a specialized white blood cell called a myelocyte. The cancerous change often takes place in the bone marrow, where all blood cells are made. CML is slow to develop and may affect a person for many years.

What is going on in the body?

When the cancerous cells grow in the bone marrow, normal bloods cells are often destroyed or crowded out. Having fewer normal white cells can cause the person to become infected easily. The infections may be serious and life-threatening. Having fewer platelets means that the person may bruise or bleed easily. Anemia, or low numbers of red blood cells, can make the person weak and easily tired.

CML cells eventually leave the bone marrow and travel throughout the body in the bloodstream. So many CML cells may enter the bloodstream that the blood becomes too thick. The number of CML cells may be as many as a 150 times the normal amount of white cells. However, these CML cells do not function like normal white cells.

What are the causes and risks of the disease?

The cause of CML is unknown.

What are the signs and symptoms of the disease?

Many times, CML causes no symptoms and is found only when a routine blood sample is checked. The most common symptom is severe fatigue. The person may also have unexplained weight loss and night sweats. Occasionally, the person can feel pain in the upper left side of the abdomen due to a swollen spleen.

How is the disease diagnosed?

Diagnosis of CML begins with a medical history and physical exam. A blood sample is examined to look for cancerous cells. Genetic studies may be done on the blood sample as well. This helps to identify any special characteristics of the leukemia. A sample of bone marrow will be removed and examined as well. This procedure is known as bone marrow biopsy.

What can be done to prevent the disease?

There is no known prevention for CML.

What are the long-term effects of the disease?

The early part of the disease, when it is causing few problems, is called the chronic phase. Eventually, CML cells will begin multiplying very rapidly. At that time, the disease will be similar to acute nonlymphatic leukemia. CML is said to be in terminal phase because there are so many immature white cells in the body. At that point the disease is difficult to treat and may lead to death. This may happen several months or years after the disease is diagnosed.

What are the risks to others?

CML is not contagious and poses no risk to others.

What are the treatments for the disease?

Chemotherapy with medicines such as hydroxyurea or busulfan may decrease the numbers of CML cells for many years. Interferon, a natural substance produced by white cells, may also help the body control the CML cells. Known as a biological response modifier, interferon does not cure the cancer. It can only control it for a period of time.

Some people are given the bone marrow from another person to help recovery. This is called a bone marrow transplant. A bone marrow transplant during this phase may cure the person. This therapy is very intense and may not be right for every person who has CML.

During the terminal phase, CML will be treated like acute leukemia. High doses of chemotherapy may be given in the veins. If the cancerous cells can be destroyed, which is a stage known as remission, the person may be considered for a bone marrow transplant. Remission is usually followed by additional therapy.

What are the side effects of the treatments?

Chemotherapy given during the chronic phase causes only mild side effects. Mild nausea will usually pass with time. The medicines given during the terminal phase cause many side effects. Interferon can cause long-term flu-like symptoms.

The effects of bone marrow transplantation are severe and life-threatening. The person will be in a facility that specializes in bone marrow transplants. Intensive care will be given to manage any side effects and problems.

What happens after treatment for the disease?

The person with CML will need to be followed closely for signs of the disease worsening. Persons who have had a bone marrow transplant will need lifelong follow-up even if the disease is in remission.

How is the disease monitored?

During the chronic phase, blood samples will be monitored closely for signs that the CML is not under control. When this happens, a bone marrow biopsy will be done. If the person is in a remission, blood samples will again be monitored closely. Bone marrow biopsies will also be done, if necessary. Any new or worsening symptoms should be reported to the healthcare provider.