Recently, many new drugs have been developed for the treatment of Waldenström macroglobulinemia (WM). To optimize the treatment according to the prognosis and to facilitate the comparison of trials, we developed an International Prognostic Scoring System for WM in a series of 587 patients with clearly defined criteria for diagnosis and for initiation of treatment. The median survival after treatment initiation was 87 months. Five adverse covariates were identified: advanced age (>65 years), hemoglobin less than or equal to 11.5 g/dL, platelet count less than or equal to 100 × 10⁹/L, β2-microglobulin more than 3 mg/L, and serum monoclonal protein concentration more than 7.0 g/dL. Low-risk patients (27%) presented with no or 1 of the adverse characteristics and advanced age, intermediate-risk patients (38%) with 2 adverse characteristics or only advanced age, and high-risk patients (35%) with more than 2 adverse characteristics. Five-year survival rates were 87%, 68%, and 36%, respectively (P < .001). The ISSWM retained its prognostic significance in subgroups defined by age, treatment with alkylating agent, and purine analog. Thus, the ISSWM may provide a means to design risk-adapted studies. However, independent validation and new biologic markers may enhance its significance.

Solitary plasmacytoma is an infrequent form of plasma cell dyscrasia that presents as a single mass of monoclonal plasma cells, located either extramedullary or intraosseous. In some patients, a bone marrow aspiration can detect a low monoclonal plasma cell infiltration which indicates a high risk of early progression to an overt myeloma disease. Before treatment initiation, whole body positron emission tomography–computed tomography or magnetic resonance imaging should be performed to exclude the presence of additional malignant lesions. For decades, treatment has been based on high-dose radiation, but studies exploring the potential benefit of systemic therapies for high-risk patients are urgently needed. In this review, a panel of expert European hematologists updates the recommendations on the diagnosis and management of patients with solitary plasmacytoma.