Gareth J. Morgan

PURPOSE: There is a need for a simple, reliable staging system for multiple myeloma that can be applied internationally for patient classification and stratification. PATIENTS AND METHODS: Clinical and laboratory data were gathered on 10,750 previously untreated symptomatic myeloma patients from 17 institutions, including sites in North America, Europe, and Asia. Potential prognostic factors were evaluated by univariate and multivariate techniques. Three modeling approaches were then explored to develop a staging system including two nontree and one tree survival assessment methodologies. RESULTS: Serum beta2-microglobulin (Sbeta2M), serum albumin, platelet count, serum creatinine, and age emerged as powerful predictors of survival and were then used in the tree analysis approach. A combination of Sbeta2M and serum albumin provided the simplest, most powerful and reproducible three-stage classification. This new International Staging System (ISS) was validated in the remaining patients and consists of the following stages: stage I, Sbeta2M less than 3.5 mg/L plus serum albumin > or = 3.5 g/dL (median survival, 62 months); stage II, neither stage I nor III (median survival, 44 months); and stage III, Sbeta2M > or = 5.5 mg/L (median survival, 29 months). The ISS system was further validated by demonstrating effectiveness in patients in North America, Europe, and Asia; in patients less than and > or = 65 years of age; in patients with standard therapy or autotransplantation; and in comparison with the Durie/Salmon staging system. CONCLUSION) The new ISS is simple, based on easy to use variables (Sbeta2M and serum albumin), and recommended for early adoption and widespread use.

PURPOSE: The clinical outcome of multiple myeloma (MM) is heterogeneous. A simple and reliable tool is needed to stratify patients with MM. We combined the International Staging System (ISS) with chromosomal abnormalities (CA) detected by interphase fluorescent in situ hybridization after CD138 plasma cell purification and serum lactate dehydrogenase (LDH) to evaluate their prognostic value in newly diagnosed MM (NDMM). PATIENTS AND METHODS: Clinical and laboratory data from 4,445 patients with NDMM enrolled onto 11 international trials were pooled together. The K-adaptive partitioning algorithm was used to define the most appropriate subgroups with homogeneous survival. RESULTS: ISS, CA, and LDH data were simultaneously available in 3,060 of 4,445 patients. We defined the following three groups: revised ISS (R-ISS) I (n = 871), including ISS stage I (serum β2-microglobulin level < 3.5 mg/L and serum albumin level ≥ 3.5 g/dL), no high-risk CA [del(17p) and/or t(4;14) and/or t(14;16)], and normal LDH level (less than the upper limit of normal range); R-ISS III (n = 295), including ISS stage III (serum β2-microglobulin level > 5.5 mg/L) and high-risk CA or high LDH level; and R-ISS II (n = 1,894), including all the other possible combinations. At a median follow-up of 46 months, the 5-year OS rate was 82% in the R-ISS I, 62% in the R-ISS II, and 40% in the R-ISS III groups; the 5-year PFS rates were 55%, 36%, and 24%, respectively. CONCLUSION: The R-ISS is a simple and powerful prognostic staging system, and we recommend its use in future clinical studies to stratify patients with NDMM effectively with respect to the relative risk to their survival.