title: Long-term follow-up of IgM monoclonal gammopathy of undetermined significance.
abstract: Little effort has been made to quantitate adverse outcomes of monoclonal gammopathy of undetermined significance (MGUS) of the immunoglobulin M (IgM) class, which progresses to lymphoma or Waldenström macroglobulinemia, whereas IgA and IgG MGUS progress to multiple myeloma, primary amyloidosis (AL), or a related plasma cell disorder. From 1960 to 1994, IgM MGUS was diagnosed in 213 patients in southeastern Minnesota. The end point was progression to lymphoma or a related disorder, as assessed with the Kaplan-Meier method. The 213 patients were followed up for 1567 person-years (median, 6.3 years per patient). Lymphoma developed in 17 patients (relative risk [RR], 14.8), Waldenström macroglobulinemia in 6 (RR, 262), primary amyloidosis in 3 (RR, 16.3), and chronic lymphocytic leukemia in 3 (RR, 5.7). The relative risk of progression was 16-fold higher in the patients with IgM MGUS than in the white population of the Iowa Surveillance, Epidemiology, and End Results Program. Cumulative incidence of progression was 10% at 5 years, 18% at 10 years, and 24% at 15 years. On multivariate analysis, the serum monoclonal protein and serum albumin concentrations at diagnosis were the only risk factors for progression to lymphoma or a related disorder. Risk for progression to lymphoma or a related disorder at 10 years after the diagnosis of MGUS was 14% with an initial monoclonal protein concentration of 0.5 g/dL or less, 26% with 1.5 g/dL, 34% for 2.0 g/dL, and 41% for more than 2.5 g/dL.
authors.affiliation: Division of Hematology and Internal Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA. kyle.robert@mayo.edu
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kyle
authors.forename: Terry M
authors.initials: TM
authors.lastname: Therneau
authors.forename: S Vincent
authors.initials: SV
authors.lastname: Rajkumar
authors.forename: Ellen D
authors.initials: ED
authors.lastname: Remstein
authors.forename: Janice R
authors.initials: JR
authors.lastname: Offord
authors.forename: Dirk R
authors.initials: DR
authors.lastname: Larson
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Plevak
authors.forename: L Joseph
authors.initials: LJ
authors.lastname: Melton
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000686:Amyloidosis / Q000209:etiology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000209:etiology; D008223:Lymphoma / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010265:Paraproteinemias / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D011379:Prognosis; D012307:Risk Factors; D016019:Survival Analysis; D008258:Waldenstrom Macroglobulinemia / Q000209:etiology
chemical_list: D007075:Immunoglobulin M