Prognostication in young and old patients with Waldenström's macroglobulinemia: importance of the International Prognostic Scoring System and of serum lactate dehydrogenase.

We analyzed 232 patients with previously untreated, symptomatic WM, of whom 10% were < or = 50 years of age and 21% were > 75 years of age. Disease features and response to treatment were similar among age groups. Patients > 75 years of age had significantly shorter survival (OS; 53 months vs. 113 months for those > 50-75 years vs. not reached for patients < or = 50 years of age; P < .001). Despite the fact that 33% of elderly patients died of causes unrelated to WM, disease-specific survival (DSS) was 72 months for patients > 75 years, 120 months for those > 50-75 years and not reached for patients < or = 50 years (P = .001). International Prognostic Scoring System for WM (IPSSWM) could discriminate 3 risk groups with significantly different OS or DSS. The addition of elevated serum lactate dehydrogenase in the IPSS improved the ability of IPSS to identify a group of patients with a significantly worse outcome (median survival, 55 months).