MINIMAL RESIDUAL DISEASE STATUS IMPROVED THE RESPONSE EVALUATION IN PATIENTS WITH WALDENSTRöM’S MACROGLOBULINEMIA

Abstract

Minimal residual disease (MRD) has been recognized as an important prognostic factor for survival in hematological malignancies. However, the prognostic value of MRD in Waldenström’s macroglobulinemia (WM) remains largely unexplored. We analyzed 108 newly diagnosed WM patients receiving systematic therapy and assessed MRD by multiparameter flow cytometry (MFC) in the bone marrow. At best response, 34 patients (31.5%) achieved undetectable MRD (uMRD). Hemoglobin > 115 g/L (p = 0.03), serum albumin >35 g/L (p = 0.01), β2-MG ≤ 3 mg/L (p = 0.03), and low-risk International Prognostic Scoring System for WM (IPSSWM) stage (p < 0.01) were associated with a higher rate of uMRD. Improvements in IgM (p < 0.01) and hemoglobin (p = 0.03) were more evident in uMRD patients compared with MRD-positive patients. The 3-year progression-free survival (PFS) was better for uMRD patients compared with those MRD-positive patients (96.2% vs. 52.8%; p = 0.0012). Landmark analysis also showed that uMRD patients had a better PFS than MRD-positive patients after 6 and 12 months. Patients who achieved partial response (PR) and uMRD had a 3-year PFS of 100%, which was significantly higher than that patients with MRD-positive PR (62.6%, p = 0.029). Multivariate analysis showed that MRD positivity was an independent factor for PFS (HR 2.55, p = 0.03). Moreover, the combination of the 6th International Workshop on WM assessment (IWWM-6 Criteria) and MRD had a higher 3-year AUC compared with the IWWM-6 criteria only (0.71 vs. 0.67). MRD based on MFC was an independent prognostic factor for survival in WM, which could improve the precision of response evaluation, especially for patients who had obtained PR. Keywords: diagnostic and prognostic biomarkers, indolent non-Hodgkin lymphoma No conflicts of interests pertinent to the abstract.