CLL is one of the most common forms of leukemia in adults. One kind of CLL [early stage low and intermediate risk (described later)] grows very slowly and rarely needs to be treated. People with this type of CLL survive an average of 15 years or more. The other kind of CLL (high risk) grows faster and is more serious. People with this kind of CLL live an average of about 8 years. 

The Leukemia & Lymphoma Society

Memorial Sloan-Kettering Cancer Center

OncoLink (Abramson Cancer Center " U Penn)

Dana-Farber/Brigham & Women's Cancer Center

​Hairy Cell Leukemia (a subtype of CLL)