What should people know about leukemia?
Leukemia is cancer of the blood cells. Blood is made up of a fluid, called plasma, and three types of cells that are made in the bone marrow. Each has its own function:
- white blood cells (also called WBCs or leukocytes). These cells help the body fight infections and diseases.
- red blood cells (also called RBCs or erythrocytes). These cells carry oxygen from the lungs to other parts of the body and take carbon dioxide back to the lungs.
- platelets (also called thrombocytes). These cells help form blood clots that control bleeding.
Leukemia occurs when the bone marrow makes abnormal blood cells, usually white blood cells, which do not function as they should. The abnormal cells survive longer, build up in large numbers, and enter the bloodstream. Normal cells, crowded out by the abnormal cells, cannot work properly and the person becomes ill with leukemia.
There are several different types of leukemia. The different types are classified by how quickly the disease progresses (acute or chronic), and by the type of blood cell affected. The most common types of leukemia are:
- acute lymphocytic leukemia (ALL). ALL is the most common type of leukemia in children. It also affects adults, especially those age 65 and older. ALL affects the lymphocytic type of white blood cells.
- acute myeloid leukemia (AML). AML occurs in both adults and children and is sometimes called acute non-lymphocytic leukemia. AML affects the myeloid (also known as nonlymphocytic) type of white blood cells, the red blood cells and the cells that make platelets.
- chronic lymphocytic leukemia (CLL). CLL most commonly affects adults over age 55 and rarely occurs in children. CLL affects the lymphocytic type of white blood cells.
- chronic myeloid leukemia (CML). CML occurs mainly in adults, but a small number of children also get this form of leukemia. CML affects the myeloid (also known as nonlymphocytic) type of white blood cells, the red blood cells and the cells that make platelets.
Each year in New York State, almost 2,200 men and over 1,500 women (including children) get leukemia. Almost 800 men and about 600 women, again including children, in New York die from this disease each year.
The five-year survival rate for leukemia has tripled in the past 50 years. For children, the improvement in survival has been even more dramatic. In 1960, only 4% of children with the most common form of childhood leukemia (ALL) lived five years. Now, the five-year survival rate for children with ALL is over 85%.
Who gets leukemia?
Although it is often thought of as a children's disease, most cases of leukemia occur in older adults. More than half of all leukemia cases occur in people over the age of 65.
What factors increase risk for developing leukemia?
At this time, the causes of leukemia are not well understood. However, scientists agree that certain factors increase a person's risk of developing this disease. These risk factors include:
- Genetics. People with Down syndrome and certain other genetic conditions get leukemia more frequently.
- Ionizing radiation. Exposure to high doses of ionizing radiation (such as radiation treatment for other cancers) has been associated with the development of all types of leukemia except CLL.
- Medications. People treated with certain types of anti-cancer drugs (such as alkylating agents) are at greater risk for getting leukemia.
- Workplace exposures. Long-term exposure to chemicals such as benzene and ethylene oxide has been shown to increase risk for getting leukemia.
- Smoking. Researchers believe that up to 20% of acute myeloid leukemias (AMLs) may be caused by smoking.
- Blood disorders. People with certain disorders of blood cell formation, including polycythemia vera, essential thrombocytopenia and chronic myeloid leukemia (CML) are at higher risk of developing acute myeloid leukemia (AML).
- Viruses. Certain unusual forms of leukemia are caused by a rare virus.
What other risk factors for leukemia are scientists studying?
Scientists are continuing to study other chemicals that people may be exposed to in the workplace. These include organic solvents, pesticides, herbicides and hair dyes.
Some early studies suggested that childhood leukemia may be associated with exposure to electromagnetic fields, such as those from power lines. Some other studies did not confirm this, except possibly when the strength of the fields was extremely high. The ways by which this low-energy type of radiation might affect cancer risk are not clear.
Many scientists are interested in whether childhood leukemia may be related to infections a child has had. Other risk factors for childhood leukemia being investigated include having a high birth weight (3500 grams/7.7 pounds or more), a mother who was older (over age 35) at the time of the child's birth, and exposures the child's parents may have had.
What can I do to reduce my chances of getting leukemia?
To help reduce the risk of getting leukemia:
- Be aware of your family history and discuss any concerns with your health care provider.
- Discuss the risks and benefits of medical imaging, such as CT scans and x-rays, with your health care provider to avoid unnecessary exposure to ionizing radiation. This is particularly important for children and pregnant women.
- Be aware of workplace health and safety rules and follow them.
- Do not smoke. If you currently smoke, quit. Avoid exposure to second hand smoke. For more information on quitting smoking, visit the NYS Smoker's Quitline at www.nysmokefree.com or call 1-866-NY-QUITS.
How else can I reduce my risk for cancer?
The following may help reduce the risk of developing cancer:
- Exercise regularly.
- Choose a healthy diet to achieve and maintain a healthy weight. Eat more vegetables, fruits and whole grains and eat less red and processed (e.g., bacon, sausage, luncheon meat, hot dogs) meats. These actions may reduce the risk of developing many types of cancer as well as other diseases.
- Talk with your health care provider about recommended cancer screenings.