Overview

Chronic lymphocytic leukemia (CLL) is a type of cancer of the blood and bone marrow — the spongy tissue inside bones where blood cells are made.

The term "chronic" in chronic lymphocytic leukemia comes from the fact that this leukemia typically progresses more slowly than other types of leukemia. The term "lymphocytic" in chronic lymphocytic leukemia comes from the cells affected by the disease — a group of white blood cells called lymphocytes, which help your body fight infection.

Chronic lymphocytic leukemia most commonly affects older adults. There are treatments to help control the disease.