Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) develops when changes happen in certain genes and chromosomes over time. The exact cause of these changes is unknown, but some factors can raise a person’s risk of developing CLL.

The risk of CLL increases with age. 9 out of 10 people with CLL are over the age of 50, with the average age at diagnosis being 71 years old.^{2 4} CLL is more common in men and in White individuals. Having a close family member with CLL increases risk, making someone 2 to 4 times more likely to develop CLL.² Other risk factors include exposure to certain chemicals, such as some herbicides and insecticides, and having monoclonal B-cell lymphocytosis (MBL), a condition in which your body produces too many lymphocytes (a type of white blood cell).

Healthcare providers use staging to understand how advanced chronic lymphocytic leukemia (CLL) is and to help guide treatment decisions. CLL is staged using blood tests and physical exams. These tests also help determine whether the disease is likely to progress or whether treatment is needed. Two similar staging systems are used for CLL:

Rai Staging System More commonly used in the United States. Stage 0 is considered low risk, stages I and II are intermediate risk and stages III and IV are high risk.

• Rai stage 0: Lymphocytosis with no enlargement of the lymph nodes
• Rai stage I: Lymphocytosis with enlarged lymph nodes
• Rai stage II: Lymphocytosis with enlarged spleen or liver
• Rai stage III: Lymphocytosis with low red blood cell counts
• Raid stage IV: Lymphocytosis with enlarged lymph nodes, spleen or liver, and with low platelet and red blood cell counts

Binet Staging System More commonly used in Europe. Stage A is considered low risk, stage B is intermediate risk and stage C is high risk. Lymphoid tissue is part of the lymphatic system and helps store lymphocytes.

• Binet stage A: Less than 3 areas of lymphoid tissue are enlarged
• Binet stage B: At least 3 areas of lymphoid tissue are enlarged
• Binet stage C: Any number of lymphoid tissue areas are enlarged with a presence of low red blood cell counts (anemia) and/or low platelet counts (thrombocytopenia)

To diagnose chronic lymphocytic leukemia (CLL), your doctor will often begin with a physical examination. During this visit, they may check for swollen lymph nodes or an enlarged spleen. If CLL is suspected, several tests can help confirm diagnosis and guide next steps.

• Complete blood count (CBC) with differential: Measures the number of red blood cells, white blood cells, and platelets and the different types of white blood cells in your blood
• Peripheral blood smear: Shows the size, shape and appearance of cells
• Flow cytometry: Determines if the white blood cells are carrying CLL cells
• Genetic tests: Identifies changes in the cancer cell DNA to best determine how to treat CLL
• Bone marrow biopsy and aspiration: Looks for leukemia cells in the inner parts of specific bones, where new blood cells are created
• Imaging: Computed tomography (CT) and/or positron emission tomography (PET) scans to show enlarged lymph nodes or organs

Chronic lymphocytic leukemia (CLL) usually develops slowly, and many people live for years without noticing symptoms. When treatment becomes necessary, there are effective options that can control the disease and bring it into remission, often for long periods of time. If CLL returns, other treatments may be used to help manage it again.

Outlook varies from person to person and depends on several factors, including age, how advanced the disease is, and certain biological features of the cancer. Doctors use a scoring system to help estimate prognosis, with lower scores being linked to better outcomes. Survival rates for CLL have improved over time, and advances in treatment continue to make a positive difference. While CLL is a long-term condition, many people can live long, active and meaningful lives with proper care.

Researchers are continuously investigating potential new and more effective treatments. For guidance on the best treatment options for you—and to determine if you may qualify for a clinical trial—please speak with your healthcare provider.