Leukemia is cancer of the body’s white blood cells; It develops in the bone marrow and lymphatic system and then spills into the bloodstream. The four types of leukemia are divided into two categories: acute and chronic. Acute leukemia involves immature cells, called stem cells, while chronic leukemia develops in mature cells. However, there is much more to understand about these two types of leukemia, including their subcategories.
Acute leukemias progress quickly because they affect stem cells, called blasts, that divide rapidly — both normal blood cells and cancer cells. The problem is that abnormal cells enter the bloodstream quickly because they don’t stop dividing when needed. Because they grow so quickly, acute leukemias often spread to a person’s organs and central nervous system. Many people with acute leukemia will experience easy bleeding and bruising, fatigue, unintended weight loss, and frequent infections.
This is a serious form of cancer. If left untreated, the prognosis of acute leukemia is dire, with most people surviving only a few months. However, some types of acute leukemia can be cured with proper treatment.
There are two types of acute leukemia:
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Acute lymphocytic leukemia (also called lymphoblastic leukemia) (ALL): This type of cancer develops when abnormally immature lymphocytic white blood cells begin to divide out of control. Mature lymphocytes are responsible for making antibodies.
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Acute myeloid (also called myeloid) leukemia (AML): This disease can start with immature white blood cells that are different from those that have become lymphocytes. It also develops in other types of immature blood cells – red blood cells and platelets. AML has several subtypes, classified by the type and maturity of the cells in which the disease develops.
Women are more likely to develop ALL than men, especially starting after age 45. Men are more likely to develop all other types of leukemia. Children are also more likely to develop ALL than AML. About 75% of all childhood leukemias are ALL, the rest are AML.
Treatments can be effective for people with acute leukemia, especially ALL. More than 80% of patients are in complete remission, and about 40% are cured. Types of treatment include:
- Chemotherapy
- Stem cell transplant, which replaces a person’s bone marrow with new marrow
- Radiation therapy, which uses X-rays to kill cancer cells, is often used when the cancer has spread to the central nervous system.
- Drugs that target, attack a specific aspect of cancer cells
- Clinical trials test new treatments and procedures
In chronic leukemia, the abnormal cells are partially mature and often appear normal. When these cells develop into leukemia cells, they also don’t fight disease, and they outlast normal white blood cells, allowing them to build up in the blood.
These cancers progress more slowly than acute leukemia. People often show no symptoms and can live many years after the onset of the disease. However, chronic leukemias don’t respond well to treatment, making them harder to cure.
There are two types of chronic leukemia:
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Chronic lymphocytic leukemia (CLL): This disease develops from partially mature white blood cells called lymphocytes. It starts in the bone marrow but then moves into the bloodstream. There are two types of CLL, one that develops slowly and another that is more rapid and severe.
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Chronic myelogenous leukemia (CML): This form of leukemia begins with genetic changes in non-lymphoid white blood cells, red blood cells, and platelets. An abnormal gene then begins to turn normal cells into CML cells. Although this is a slow-growing type of leukemia, it can also turn into acute, fast-growing leukemia.
Men develop chronic leukemia at a much higher rate than women, although CML is uncommon in both sexes and all age groups. Chronic leukemia is rare in children.
Treatment includes:
- Targeted Drugs
- Biologic therapy with monoclonal antibodies: man-made drugs that help the immune system destroy cancer cells, used mainly with CLL
- Biologic therapy with interferon: injections of substances made in the immune system, used mainly with CML
- Chemotherapy
- Stem cell transplant
- Clinical trials test new treatments and procedures
Understanding the difference between acute and chronic forms of leukemia is important in forming an action plan to deal with the disease. Talk to your doctor about your symptoms and the best treatment plan for your condition.
