Chronic Lymphocytic Leukemia (CLL)

What Is Chronic Lymphocytic Leukemia (CLL)? Chronic lymphocytic leukemia (CLL) is a type of blood cancer that affects the bone marrow and blood. In a healthy body, blood stem cells mature into red blood cells, platelets, and white blood cells (lymphocytes) that help fight infection. In CLL, too many blood stem cells develop into abnormal lymphocytes, also called leukemia cells. These cells do not function properly and cannot fight infections effectively. As they accumulate in the bone marrow and bloodstream, they crowd out healthy blood cells. This can lead to anemia, increased risk of infections, and easy bruising or bleeding. CLL is considered a chronic leukemia, meaning it usually progresses slowly over time. Risk Factors for CLL The main risk factors associated with CLL include: Family history of CLL Family history of cancers of the lymphatic system Age over 70 Male sex White ethnicity Exposure to Agent Orange CLL does not appear to be linked to diet, infections, or smoking. Symptoms of CLL CLL often develops silently. Many people have the disease for years without symptoms and are diagnosed incidentally during routine blood tests for unrelated conditions. When symptoms do appear, they may include: Fatigue and weakness Enlarged lymph nodes (felt as painless lumps under the skin) Abdominal discomfort or a feeling of fullness due to an enlarged spleen Unexplained weight loss Night sweats Frequent or severe infections Types of CLL There are two main biological forms of CLL: Slow-growing (indolent) CLL, which may not require treatment for many years Faster-growing (aggressive) CLL, which progresses more rapidly and requires earlier treatment The difference between these types cannot be determined by symptoms alone. Specialized laboratory and genetic testing are required to identify the form of CLL and guide treatment decisions.