Types of Leukemia
Leukemia is not one disease, but several— and while they all affect the blood, not all are created equal. In fact, there are many types of leukemia. Some are more common in children, while others are more common in adults. Some leukemias are considered ‘acute’ and others, ‘chronic.’ There are even those that emerge from ‘myeloid’ cells versus ‘lymphoid’ cells. At Rocky Mountain Cancer Centers (RMCC), we feel that it’s important to bring clarity to some of the confusion that can surround leukemia. Understanding more about your type is an important step toward understanding your treatment.
Generally, leukemias are categorized by which type of blood cell they arise from and how quickly they progress. Fast-growing leukemias are called acute, while slower-growing leukemias are called chronic. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.
There are four common types of leukemia:
- Chronic lymphocytic leukemia (CLL): CLL, the most common type of leukemia, affects lymphoid cells and usually grows slowly. It accounts 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.
- Acute myeloid leukemia (AML): AML affects myeloid cells and grows quickly. It is the most common type of acute leukemia, accounting for more than 13,000 new cases of leukemia each year. While it does occur in children, it occurs most often in adults.
- Chronic myeloid leukemia (CML): CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.
- Acute lymphocytic (lymphoblastic) leukemia (ALL): ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children, however, it also affects adults.
Another type of leukemia is hairy cell leukemia. Hairy cell leukemia is a rare type of leukemia in which abnormal B-lymphocytes (a type of white blood cell) are present in the bone marrow, spleen, and peripheral blood. When viewed under a microscope, these cells appear to be covered with tiny hair-like projections.