Retrospective analysis of prognostic factors for Waldenstrӧm macroglobulinemia: a multicenter cooperative study in Japan.

Although population-based cancer registries have reported lower incidence of Waldenstrӧm macroglobulinemia (WM) in East Asia than in Western countries, previous retrospective analyses have found the clinical features of WM to be similar in these two populations. To clarify the characteristics of Japanese WM patients, we retrospectively analyzed clinical and laboratory characteristics, treatments, outcomes, and prognostic factors in 93 patients with WM. Based on the Second International Workshop on WM (IWWM-2) criteria, symptomatic WM was found in 73 (78.5%) and asymptomatic WM in 20 (21.5%) of cases examined. The median overall survival (OS) was similar to that in reports from Western countries. Patients receiving treatment regimens including rituximab exhibited significantly better survival than those not given rituximab. Although prognostic factors for WM in Western countries may not apply to Japanese patients, our finding that newly diagnosed WM patients with pleural effusion have a poorer prognosis suggests that this may be a novel predictor of adverse prognosis in symptomatic WM.