Each year in the United States, more than 40,800 adults and 3,500 children are diagnosed with leukemia.
Beginning in the blood-forming tissues, leukemia causes bone marrow (the soft sponge-like tissue in the center of bones) to produce large numbers of abnormal white blood cells.
As part of the immune system, the role of white blood cells is to help defend the body against both infectious disease and foreign materials. In a person with leukemia, abnormal white blood cells don't function normally and don't die off when they should, like other blood cells.
This large number of abnormal white blood cells interferes with the functioning of normal white blood cells, platelets (disk-shaped structures that help blood to clot) and red blood cells, which travel through the blood to deliver oxygen to body tissues.
The following four common types of leukemia are grouped by 1) the type of white blood cell that is affected and 2) whether the disease is chronic (usually gets worse slowly) or acute (usually gets worse quickly).
Types of Leukemia
Chronic Lymphocytic Leukemia (CLL)
CLL affects lymphoid cells and usually grows slowly, accounting for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55; it almost never affects children.
Chronic Myeloid Leukemia (CML)
CML involves the myeloid cells and accounts for nearly 5,000 new cases of leukemia each year. Mainly affecting adults, this disease usually grows slowly at first.
Acute Lymphocytic (Lymphoblastic) Leukemia (ALL)
ALL grows quickly, affecting the lymphoid cells. Causing more than 5,000 new cases of leukemia each year, ALL is the most common type of leukemia in young children, though it also affects adults.
Acute Myeloid Leukemia (AML)
Occurring in both adults and children, AML affects myeloid cells and grows quickly, accounting for more than 13,000 new cases of leukemia each year.
Symptoms of Leukemia
Common symptoms of chronic or acute leukemia may include:
- Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)
- Swelling or discomfort in the abdomen (from a swollen spleen or liver)
- Feeling weak or tired
- Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)
- Weight loss for no known reason
- Frequent infections
- Fevers or night sweats
- Pain in the bones or joints
These symptoms can also be a sign of an infection or other health problem. Be sure to see your doctor if you are experiencing these problems.