Leukemia is a broad term that describes cancer of the body’s blood-forming tissues, including the bone marrow and the lymphatic system.
There are many types of leukemia, and while it is a common childhood cancer, leukemia actually occurs more often in older adults. Leukemia is the most common cancer in people under the age of 15, but it is most likely to affect people who are 55 or older.
There are four main types of leukemia: chronic, acute, lymphocytic, and myelogenous.
- Chronic leukemia grows slowly . The cancer cells form very slowly so the body can also continue to form healthy cells, but over time the cancer cells continue to grow and the leukemia worsens.
- Acute leukemia grows very quickly and gets worse really fast. It has been identified as the most rapidly progressing cancer, and it can develop and grow in a matter of days or weeks.
- Lymphocytic leukemia forms in the part of the bone marrow that makes lymphocytes, which are white blood cells that are also immune cells. Chronic lymphocytic leukemia (CLL) is most common in older adults and makes up about 25 percent of adult leukemia cases. It is more common in men than women and is very rare in children. Acute lymphoblastic leukemia (ALL) also affects older adults, but children younger than five have the highest risk of developing it.
- Myelogenous leukemia forms in the bone marrow cells that produce blood cells, rather than forming in the actual blood cells. Chronic myelogenous leukemia (CML) accounts for about 15 percent of all leukemia cases in the United States. CML develops mostly in adults and is very rare in children. Acute myelogenous leukemia (AML) is a rare cancer that develops quickly with symptoms of fever, difficulty breathing, and pain in the joints. It can be caused by environmental factors, and develops more often in adults than children, and more often in men than women.
Learn more about these specific types of leukemia: