CLINICAL FEATURES AND SURVIVAL OUTCOMES ON LYMPHOPLASMACYTIC LYMPHOMA PATIENTS WITH NON-IGM PARAPROTEINEMIA COMPARED WITH IGM PARAPROTEINEMIA IN KOREA

Introduction: The incidence of lymphoplasmacytic lymphoma (LPL), a relatively rare subset of non-Hodgkin lymphoma, has been suggested lower in Asian population than in Western countries. Non-IgM LPL is rare and accounts for less than 5% of the total LPL cases. There have been few studies comparing the clinical features and survival outcomes between patients with non-IgM LPL and LPL/Waldenström macroglobulinemia (WM) in East Asia. In this study, we evaluated clinical features and survival outcomes of LPL with non-IgM compared with LPL/WM in Korea. Method: A retrospective analysis was performed for patients diagnosed with non-IgM LPL and LPL/WM at Asan Medical Center between January 2001 and March 2016. Clinical features and survival outcomes were compared between the two groups. Result: A total of 19 patients were categorized into non-IgM (n = 8, 42.1%) and LPL/WM (n = 11, 57.8%) groups. The median age at diagnosis was 65.5 (62 to 69) and 57 (range 47 to 66) years, respectively; 7 (87.5%) patients in non-IgM LPL and all patients in LPL/WM were men. There were no statistically significant differences in baseline characteristics between non-IgM LPL and LPL/WM groups, except the proportion of high/high-intermediate subset according to International prognostic index (IPI) (75% vs 18.2%, p = 0.024). The patients in LPL with non-IgM group more frequently showed extranodal involvement of ≥2 (62.5% vs. 27.3%) and demonstrated higher level of beta-2-microglobuin level than those in LPL/WM group [median, 12.8, (range, 2.3–41.0) vs. 3.7, (2.2–30.0)] without statistical significance. Patients were treated with heterogeneous regimens including CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone), CVP (cyclophosphamide, vincristine, prednisone), and fludarabine. The median overall survival of the LPL with non-IgM group was shorter than that of LPL/WM (10 months [95% CI, 0–36.3] vs median 81 months [95% CI, 0–168]; p = 0.124). Conclusion: Despite a small number of patients and heterogeneous treatment, more unfavorable prognostic factors with regard to IPI in non-IgM LPL group might be consistent with worse survival outcomes compared to LPL/WM group. These findings suggest IPI might be useful for predicting prognosis in non-IgM LPL and LPL/WM. Further studies are needed to clarify the clinical features and survival outcomes between two groups. Keywords: lymphoplasmacytic lymphoma (LPL); lymphoplasmacytic lymphoma/Waldenstroem (LPL/WM).