Role of different hematologic variables in defining the risk of malignant transformation in monoclonal gammopathy

L. Baldini, A. Guffanti, B. M. Cesana, M. Colombi, O. Chiorboli, I. Damilano, A. T. Maiolo

Research output: Contribution to journalArticlepeer-review


The presenting clinico-hematologic features of 386 patients with nonmyelomatous monoclonal gammopathy (MG) were correlated with the frequency of malignant transformation to evaluate the most important variables conditioning its evolution into multiple myeloma (MM) or Waldenstrom macroglobulinemia (WM). Most of the patients (335) had monoclonal gammopathy of undetermined significance (MGUS: 39 IgA, 242 IgG, 54 IgM); the remaining 51 patients (12 IgA, 39 IgG) fulfilled all of the MGUS diagnostic criteria (according to Durie) except that bone marrow plasma cell (BMPC) content was 10% to 30%, and so they were defined as having monoclonal gammopathy of borderline significance (MGBS). There were no significant differences between the MGUS and MGBS groups in terms of age, sex, or median follow-up. After a median follow-up of 70 and 53 months, respectively, 23 of 335 MGUS and 19 of 51 MGBS patients had undergone a malignant evolution. Univariate analysis of the IgA and IgG patients showed that the cumulative probability of the disease evolving into MM correlated with diagnostic definition (MGBS v MGUS), BMPC content (≥10% v 5%) and reduced serum polyclonal Ig. In the IgG cases, there was also a significant correlation with detectable Bence Jones proteinuria, serum monoclonal component (MC) levels and age at diagnosis (>70 v ≤55 years). In the IgG cases as a whole, the same variables remained in the Cox model where the BMPC percentage was considered after natural logarithmic transformation and the monoclonal component as g/dL value. The relative risks of developing MM are the following: 2.4 for each 1 g/dL increase of IgG serum MC, 3.5 for detectable light chain proteinuria, 4.4 for the increase of I unit in log(e) BMPC percentage, 6.1 for age >70, 3.6 and 13.1 for a reduction in one or two polyclonal Ig. In conclusion, our study allows the identification of a particular subset of MGUS patients (MC ≤1.5 g/dL, BMPC

Original languageEnglish
Pages (from-to)912-918
Number of pages7
Issue number3
Publication statusPublished - Feb 1 1996

ASJC Scopus subject areas

  • Hematology


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