Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia is a type of cancer that affects the blood and bone marrow, in which the bone marrow produces too many B cell lymphocytes that collect in the blood, spleen, lymph nodes, and bone marrow, crowd out healthy blood cells, and malfunction; it is divided into slow-growing, or indolent, and fast-growing variants. Most people have no symptoms at diagnosis, though 5 to 10 percent may experience fever, fatigue, unexplained weight loss, loss of appetite, painless swollen lymph nodes, an enlarged spleen, or anemia, symptoms that often worsen over time. It usually begins after age 50, risk factors include family history, tobacco use, and exposure to Agent Orange or certain insecticides, and the five-year survival rate in the United States is about 89 percent.