[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.