Leukemia is a cancer that starts in blood stem cells (immature blood cells) in the bone marrow. Bone marrow is the soft, spongy material that fills the centre of most bones.
There are several different types of leukemia, first grouped by the type of blood stem cell they developed from:
- Myelogenous Leukemias develop from abnormal myeloid cells.
- Lymphocytic Leukemias (also known as Lymphoblastic Leukemias) develop from abnormal lymphoid cells.
The types of leukemia are further grouped based on how quickly the Leukemia develops and grows:
- Acute Leukemias start suddenly, developing within days or weeks. The number of Leukemia cells in the blood can rise very fast and blood cells cannot do their jobs.
- Chronic Leukemias develop slowly over months or years. They may not cause any symptoms early in the disease. Symptoms start to appear as the number of Leukemia cells in the blood or bone marrow increases.
The 4 main types of leukemia are:
- Acute Lymphoblastic Leukemia (ALL)
- Acute Myelogenous Leukemia (AML)
- Chronic Lymphocytic Leukemia (CLL)
- Chronic Myelogenous Leukemia (CML)
In 2020, 6900 new cases of leukemia are expected to be diagnosed in Canada with 3000 Canadians expected to die of the disease (Canadian Cancer Statistics, 2020).