[1368] Chronic Lymphocytic Leukemia (CLL) with Clonal B-Cell Counts of 5–10x109/L Behaves Clinically Similar to Monoclonal B Cell Lymphocytosis (MBL)

Angela D Earhart, TuDung T Nguyen, John L Frater, Anjum Hassan, Friederike Kreisel. Washington University School of Medicine, Saint Louis, MO

Background: MBL is defined as a total clonal B cell count <5x10 9 /L in asymptomatic patients, while the diagnosis of CLL requires a monoclonal B cell count ≥5x109/L. It is unclear how these criteria affect patient management and outcome. We evaluated the differences in initial presentation and disease progression (DP) between patients with <5x10x109/L (<5BL) vs. 5–10x109/L (5-10BL) and >10x109/L (>10BL) clonal B cells.
Design: Patients diagnosed from 2002-2012 with a peripheral clonal B cell population with CLL immunophenotype were included and assessed for initial presence/absence of lymphadenopathy (LAD), splenomegaly, thrombocytopenia (platelets<100K/μl), anemia (Hbg<10 g/dl), initial management, and DP. Statistical analysis was performed by Student t-test, with p <0.05 considered significant.
Results: 249 patients were studied consisting of 52 <5BLs, 57 5-10BLs and 141 >10BLs. 40% of the <5BL and 32% of the 5-10BL group had accompanying LAD. Hence, 31 cases of <5BL represented MBLs. In comparing patients with MBL vs 5-10BL with no LAD, there was no statistically significant difference in patients presenting with thrombocytopenia (0 vs 3%), anemia (3 vs 3%), or splenomegaly (0 vs 3%), nor those requiring treatment (10 vs 8%) or with DP (29 vs 21%). When all patients were included regardless of LAD status, there was no significant difference between the <5BL vs 5-10BL group in their initial presentation except thrombocytopenia (4 vs 7%; p=0.04). When the 5-10BL and >10BL groups were compared, regardless of LAD status, significant differences were seen for anemia (7 vs 15%; p= 0.029), splenomegaly (7 vs 16%; p=0.035), requiring treatment (18 vs 34%; p=0.01), and DP (26 vs 40%; p=0.02), but not for thrombocytopenia (5 vs 12 %).
Conclusions: Our results show no significant differences in the presentation, initial management, or progression rates for patients with <5BL vs 5-10BL, except for thrombocytopenia, when all patients are included regardless of LAD status. Statistically significant differences in clinical features were seen when comparing either <5BL or 5-10BL to >10BL. Overall, these findings suggest that the clinical features of <5BL and 5-10BL are virtually indistinguishable.
Category: Hematopathology

Monday, March 4, 2013 8:15 AM

Proffered Papers: Section C, Monday Morning


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