In 2000, approximately 256,000 children and adults around the world developed some form of leukemia, and 209,000 died from it. About 90% of all leukemias are diagnosed in adults.
A Wright's stained bone marrow aspirate smear of patient with precursor B-cell acute lymphoblastic leukemia.
Classification
Leukemia is clinically and pathologically subdivided into a variety of large groups. The first division is between its acute and chronic forms:- Acute leukemia is characterized by the rapid increase of immature blood cells. This crowding makes the bone marrow unable to produce healthy blood cells. Immediate treatment is required in acute leukemia due to the rapid progression and accumulation of the malignant cells, which then spill over into the bloodstream and spread to other organs of the body. Acute forms of leukemia are the most common forms of leukemia in children.
- Chronic leukemia is distinguished by the excessive build up of relatively mature, but still abnormal, white blood cells. Typically taking months or years to progress, the cells are produced at a much higher rate than normal cells, resulting in many abnormal white blood cells in the blood. Whereas acute leukemia must be treated immediately, chronic forms are sometimes monitored for some time before treatment to ensure maximum effectiveness of therapy. Chronic leukemia mostly occurs in older people, but can theoretically occur in any age group.
