Monoclonal Proteinuria as a Prognostic Factor for Multiple Myeloma Patients with Intact Immunoglobulin Type

ABSTRACT

BACKGROUND: Urine/serum protein electrophoresis (PEP) and immunofixation electrophoresis (IEP) for monoclonal protein (M-protein) are used for initial evaluation in patients with multiple myeloma. We evaluated the prognostic significance of M-proteinuria status and its association with other prognostic factors. METHODS: Between December 2002 and December 2004, 64 de novo symptomatic multiple myeloma patients with intact immunoglobulin (Ig) type were divided into two groups according to their initial urine PEP/IEP findings. RESULTS: Twenty-seven patients with undetectable or free light-chains only were classified into F group, and 37 with whole Ig with or without light-chains were classified into W group. The two groups were similar in sex, age, performance, azotemia, beta2-microglobulin, stage and treatment, but M-protein concentration was significantly higher in the W than in F group (5.1 vs 1.3g/dL, P<0.01). The overall response rate was significantly higher in F group than in W group (80.8% vs 63.6%, P=0.02), whereas the 2-year OS rate did not differ significantly between the groups (81.0% vs 57.7%, P=0.15). CONCLUSION: Monoclonal proteinuria is helpful in identifying patients with advanced disease and poorer prognosis in multiple myeloma.