Binet Staging System for Chronic Lymphocytic Leukemia
Binet staging is a clinical prognostic classification system for chronic lymphocytic leukemia (CLL) that divides patients into three stages (A, B, C) based on the number of involved lymphoid areas and the presence of anemia or thrombocytopenia. 1
How to Apply Binet Staging
The system requires only a physical examination and routine blood counts—no imaging or bone marrow biopsy is needed for staging. 1, 2
Step 1: Count the Involved Areas
Five specific anatomical areas are assessed for lymphoid involvement (lymph nodes >1 cm or palpable organomegaly): 1
- Head and neck (including Waldeyer ring) = counts as 1 area, even if multiple node groups are enlarged
- Axillae (bilateral involvement still counts as 1 area)
- Groins (including superficial femorals; bilateral involvement counts as 1 area)
- Palpable spleen
- Palpable liver (clinically enlarged)
Step 2: Check Hemoglobin and Platelet Count
Measure hemoglobin (Hb) and platelet count to determine if cytopenias are present. 1
Step 3: Assign the Stage
Stage A: 1
- Hb ≥10 g/dL AND
- Platelets ≥100 × 10⁹/L AND
- ≤2 involved areas
- Represents ~55% of patients at diagnosis 2
- Median survival >100 months 3
Stage B: 1
- Hb ≥10 g/dL AND
- Platelets ≥100 × 10⁹/L AND
- ≥3 involved areas
- Represents ~30% of patients at diagnosis 2
- Median survival ~55-63 months 3, 4
Stage C: 1
- Hb <10 g/dL and/or
- Platelets <100 × 10⁹/L
- Regardless of number of involved areas
- Represents ~15% of patients at diagnosis 2
- Median survival ~16-45 months 3, 4
Clinical Implications
Treatment decisions are based on stage and disease activity, not just stage alone. 1
- Stage A and B without active disease: Watch and wait strategy with blood counts and clinical examinations every 3-12 months 1
- Stage A and B with active disease: Treat as advanced disease 1
- Stage C: Treatment indicated 1
Active disease is defined by: significant B-symptoms, progressive cytopenias, symptomatic lymphadenopathy/organomegaly, lymphocyte doubling time <6 months (if >30,000/µL), or autoimmune complications poorly responsive to steroids. 1
Important Caveats
Anemia and thrombocytopenia are the most powerful prognostic factors in CLL. 2 Stage C patients have the worst prognosis regardless of lymphoid involvement, which is why cytopenias override the number of involved areas in the classification. 1, 2
The Binet system may not adequately separate intermediate-risk patients. Studies show that Stage B and C patients sometimes have similar survival outcomes, suggesting the system's limitations in the modern treatment era. 3 Additionally, even Stage A patients have inferior survival compared to age- and sex-matched controls, indicating that "low-risk" CLL still carries prognostic significance. 3
The Binet system is more widely used in Europe, while the Rai system predominates in North America. 1 Both systems remain valid, though attempts to integrate them have not gained widespread adoption. 1