Monoclonal Gammopathy of Undetermined Significance and Smouldering Multiple Myeloma: Emphasis on Risk Factors for Progression

Br J Haematol. 2007 Dec;139(5):730-43. doi: 10.1111/j.1365-2141.2007.06873.x.

Abstract

Monoclonal gammopathy of undetermined significance (MGUS) is characterized by a serum monoclonal protein <30 g/l, <10% plasma cells in the bone marrow, and absence of end-organ damage (CRAB-hypercalcaemia, renal insufficiency, anaemia, or bone lesions). MGUS is present in 3% of persons >50 years and in 5% >70 years of age. The risk of progression to multiple myeloma (MM) or a related disorder is 1% per year. Patients with risk factors consisting of an abnormal serum free light chain ratio, non-immunoglobulin G (IgG) MGUS, and an elevated serum M protein >/=15 g/l had a risk of progression at 20 years of 58%, compared with 37% with two risk factors present, 21% with one risk factor present, and 5% when none of the risk factors were present. Smouldering (asymptomatic) multiple myeloma is characterized by having a serum IgG or IgA monoclonal protein of 30 g/l or higher and/or 10% or more plasma cells in the bone marrow but no evidence of end-organ damage. The cumulative probability of progression to active MM or amyloidosis was 51% at 5 years, 66% at 10 years and 73% at 15 years; the median time to progression was 4.8 years.

Publication types

  • Review

MeSH terms

  • Diagnosis, Differential
  • Disease Progression
  • Humans
  • Monoclonal Gammopathy of Undetermined Significance / diagnosis
  • Monoclonal Gammopathy of Undetermined Significance / epidemiology
  • Monoclonal Gammopathy of Undetermined Significance / etiology*
  • Multiple Myeloma / diagnosis
  • Multiple Myeloma / etiology*
  • Prevalence
  • Risk Factors