Monoclonal gammopathy of undetermined significance and evolution to myeloma: Experience in 153 patients

Introduction: Based on risk factors, the Mayo Clinic Multiple Myeloma Group (MCMMG) established a model of progression from monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM) at 20 years. It is also described that MGUS with a progressive increase of monoclonal protein (M-protein) and/or immunoparesis (IMP) may be more predisposed to progress to myeloma. Our objective was to make a review of MGUS, to see how those who presented IMP and/or progression of their M-protein, contrasting them with MGUS that presented intermediate/high and high risk according to MCMMG. Methodology and materials: A review of the MGUS objectified during the realization of a serum proteinogram (SPEP) was carried out during 2010-2014, in our area. Serum immunoglobulins, serum immunofixation (IFs), and serum free light chain ratio (FLCr) were determined for all MGUS. Results: Of the 153 MGUS that are followed up for 4 years, 6 progress to MM. Of these 6 MM, 5 progress from MGUS with intermediate/high risk taking into account the MCMMG. Of these 5, 3 have IMP or progression of their M-protein. 2 present IMP plus progression of their M-protein. The sixth MM evolves from a MGUS without any risk factor, but with progression of its M-protein plus IMP. Conclusions: IMP and/or M-protein progression are important risk factors to be taken into account in the MGUS, in the first years after diagnosis, due to their possible evolution to MM. (C) 2021 Sociedad Espanola de Medicos de Atencion Primaria (SEMERGEN). Published by Elsevier Espana, S.L.U. All rights reserved.