American Medical Association Family Medical Guide - American Medical Association [373]
Leukemias
Leukemias are cancers of white blood cells. Normally, the number of white blood cells that the body produces equals the number that die as part of the natural cycle of cell growth and death. This process is designed to keep the total number of white blood cells constant. In leukemia, abnormal white blood cells multiply at an increased rate, and these cancerous cells often tend to live longer than normal—that is, they don’t die when they should. As a result, the number of abnormal leukemia cells increases, either gradually or rapidly, accumulating in excess throughout the body and interfering with the functioning of various organs. Also, because leukemia cells are abnormal white blood cells, they usually cannot effectively eliminate infectious agents such as bacteria from the body, as healthy white blood cells can. The two main forms of leukemia affect different types of white blood cells. Myelogenous leukemia is a cancer of the cells from which white blood cells called granulocytes originate. Lymphocytic leukemias are cancers of the white blood cells from which lymphocytes originate. Both forms can be acute (short term and usually severe) or chronic (long-lasting).
Acute Myelogenous Leukemia
Acute myelogenous leukemia (AML) is caused by genetic changes in the cells that produce granulocytes, a type of white blood cell made in the bone marrow (where all the different types of blood cells are made). The resulting abnormal cells (called blasts) fail to mature properly and then multiply and survive longer than normal cells. As their numbers gradually increase, the leukemia cells pack, or fill up, the bone marrow and disrupt the production of normal white and red blood cells and platelets.
As the number of leukemia cells increases, they often spill over into the bloodstream. These cells may invade organs and tissues, especially the spleen and liver, causing the organs to become enlarged. If AML is not treated early, it can be fatal rapidly, sometimes within a few weeks. The major complications of this form of leukemia are severe infections and bleeding. However, as many as 40 to 50 percent of people with AML can be cured, depending on their age and the unique biological characteristics of their leukemia.
Symptoms
The most common symptoms of AML are feelings of fatigue, frequent infections, fever, lip, and mouth sores, and a tendency to bruise and bleed easily. The disease often occurs suddenly, with the symptoms becoming pronounced over a period of 1 to 2 weeks. In some cases, the symptoms develop gradually over about 2 months. If you have any of these symptoms, see your doctor right away.
Diagnosis
If your doctor suspects that you may have AML, he or she will examine you and will probably recommend blood tests and a bone marrow biopsy. For the biopsy, a sample of cells is withdrawn from your bone marrow through a needle and examined under a microscope for the presence of leukemia cells.
Treatment
If you are diagnosed with AML, your doctor will immediately admit you to the hospital. Because the treatment for this type of leukemia is complicated and difficult, it is usually performed by an oncologist (a doctor who specializes in treating cancer) or a hematologist (a doctor who specializes in treating blood disorders). In the hospital, you will be given transfusions of red blood cells and platelets when you need them. Platelet transfusions are usually provided to prevent bleeding. If you develop a fever or other sign of infection, the doctor will identify the infectious agent and give you antibiotics intravenously (through a vein) to fight it.
The first stage of treatment for AML is chemotherapy (see page 23) to try to destroy the cancerous cells. After a few weeks of chemotherapy, your health should return to normal. Chemotherapy produces a remission (disappearance of symptoms) in about 50 to 80 percent of people, depending on