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Clinical staging of chronic lymphocytic leukemia (CLL) is used by doctors to determine how far the disease has progressed and is a valuable tool for not only planning treatment but also for predicting the outcome (prognosis). Two staging systems have been developed for CLL are used most often to assess the progression of the disease:

• Rai staging system
• Binet staging system

Rai Staging System

Developed in 1975, the Rai classification system is used by doctors in the United States to stage patients with CLL. The Rai staging system classifies (groups) CLL patients into one of five distinct stages (Stages 0, I, II, III, or IV) based on the progressive clinical involvement of various organ systems.

In patients in the earliest stage of CLL (Stage 0), the disease is limited to the blood and bone marrow. In these patients, the only abnormality is lymphocytosis (increased numbers of lymphocytes in the bloodstream and bone marrow) without clinical evidence of other organ involvement. As the disease progresses, and other organs such as lymph nodes, spleen, liver become affected, patients are staged into the higher Rai categories (Stages I - IV).

The American Cancer Society further divides the Rai staging system according to the following risk categories based upon the stage of the disease:

• Rai Stage 0 - designated as a low risk stage
• Rai Stages I and II - designated as intermediate risk stages
• Rai Stages III and IV - designated as high risk stages

The median survival for patients with CLL based on the Rai staging system is as follows:

• Low risk group (Stage 0) = 10 years
• Intermediate risk group (Stages I and II) = 7 years
• High risk group (Stages III and IV) = 1.5 to 4 years.

Binet Staging System

The Binet staging system, developed in 1975, classifies CLL patients into the following three stages based on the number of lymph nodes involved, the presence or absence of anemia (low levels of circulating red blood cells), and thrombocytopenia (low platelet levels in the blood):

• Stage A - less than 3 areas of enlarged lymph nodes without anemia or thrombocytopenia
• Stage B - three or more areas of enlarged lymph nodes without anemia or thrombocytopenia
• Stage C - CLL associated with either anemia and/or thrombocytopenia

Prognostic Value of Staging Systems for Chronic Lymphocytic Leukemia

Both the Rai and Binet CLL staging systems provide important prognostic information in terms of predicting long-term patient survival. In general, with both staging systems, CLL patients with the lowest stage of disease (Rai Stage 0; Binet Stage A) have a median survival time of over 10 years while patients with the most advanced stage disease have a median survival time of about 1-2 years.