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Progression to MM in Patients with MGUS Assessed

N Engl J Med; 2018 Jan 18; Kyle, Larson, et al

In people with monoclonal gammopathy of undetermined significance (MGUS), progression risk appears to differ depending on whether patients have immunoglobulin M (IgM) or non-IgM MGUS, according to a study involving nearly 1,400 individuals. Participants had MGUS diagnosed at the Mayo Clinic between 1960 and 1994. Investigators followed them for a median of ~34 years, looking at progression to multiple myeloma or another plasma-cell or lymphoid disorder. Among the results:

  • MGUS progressed in 11% of patients during 14,130 person-years of follow-up.
  • Progression risk was 10% at 10 years, 18% at 20 years, 28% at 30 years, 36% at 35 years, and 36% at 40 years.
  • In patients with IgM MGUS, 55% of those with an abnormal serum free light-chain ratio and a high serum monoclonal protein level progressed by year 20.
  • Progression rates in those with 1 and none of these risks was 41% and 19%, respectively.
  • In patients with non-IgM MGUS, progression rates were 30%, 20%, and 7%, respectively.
Citation:

Kyle R, Larson D, Therneau T, et al. Long-term follow-up of monoclonal gammopathy of undetermined significance. N Engl J Med. 2018;378(3):241-249. doi:10.1056/NEJMoa1709974.