Creatinine Clearance Is More Important Prognostic Factor Than ß2 Microglobulin in Multiple Myeloma

In the new staging system of multiple myeloma (MM) by South West Oncology Group (SWOG), the concentration of serum β2 microglobulin (β2m) and serum albumin were focused as the most important prognostic factors for survival. However, serum concentration of β2m has been known as an indicator of glomerular filtration rate. The aim of this study was to compare the prognostic value of the level of β2m with that of creatinine clearance (Ccr) in patients with multiple myeloma. Retrospectively, from January 1, 1996 to November 30, 2003, we reviewed 176 MM patients (M: F 110:66 mean age: 58.5±11.0) whose 24-hour urinary creatinine clearance was available at the time of diagnosis. We collected clinical data such as hemoglobin, serum creatinine, calcium, albumin, β2m, creatinine clearance before chemotherapies, and patients’ survival time. Pretreatment β2m was inversely related to Ccr (Spearman’s correlation coefficient = −0.781, P We could propose another new staging system with β2m replaced by Ccr in SWOG staging system. The stages were defined as: stage 1, Ccr ≥ 80ml/min; stage 2, 50< Ccr In conclusion, Ccr could be more important prognostic factor than the level of β2m in patients of MM and we propose that Ccr should be reassessed as the component of staging system of MM.