Chronic Lymphocytic Leukemia: Classification

In the United States, physicians usually stage or classify each patient’s CLL according to how far the disease has progressed, using a classification approach called the Rai system.

Under this system, physicians designate CLL patients as low risk (stage 0), intermediate risk (stages I and II), or high risk (stages III and IV). These categories are based on the following signs and symptoms:

Stage 0: Lymphocyte counts are elevated (to more than 5,000 per cubic millimeter).

Stage I: Patients have both elevated lymphocyte counts and enlarged lymph nodes.

Stage II: In addition to elevated lymphocyte counts patients have an enlarged liver or spleen, with or without enlarged lymph nodes.

Stage III: Patients have elevated lymphocyte counts and a low red blood cell count (anemia), with or without swollen lymph nodes, and an enlarged liver or spleen.

Stage IV: Patients have elevated lymphocyte counts and a low number of blood platelets.

Another classification system used for CLL, the Binet system, is more common in Europe than the United States. Physicians assign patients to one of three categories according to the number of sites in the lymphatic system where disease is found (lymph nodes in the neck, underarm, groin, and spleen), and whether the patient has anemia or a low platelet count (thrombocytopenia). Patients are assigned Stage A (one or two lymphoid tissues involved; no anemia or thrombocytopenia); Stage B (three or more lymphoid tissues involved; no anemia or thrombocytopenia); or Stage C (any number of lymphoid tissues involved; anemia and thrombocytopenia).