Prevalence of smoldering multiple myeloma based on nationwide screening

• Published in: Nature medicine Vol. 29; no. 2; pp. 467 - 472
• Main Authors: Thorsteinsdóttir, Sigrún, Gíslason, Gauti K., Aspelund, Thor, Rögnvaldsson, Sæmundur, Óskarsson, Jón Þórir, Sigurðardóttir, Guðrún Á, Þórðardóttir, Ásdís R., Viðarsson, Brynjar, Önundarson, Páll T., Agnarsson, Bjarni A., Sigurðardóttir, Margrét, Þorsteinsdóttir, Ingunn, Ólafsson, Ísleifur, Eyþórsson, Elías, Jónsson, Ásbjörn, Berlanga, Oscar, Hultcrantz, Malin, Durie, Brian G. M., Löve, Thorvardur J., Harding, Stephen, Landgren, Ola, Kristinsson, Sigurður Y.
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01-02-2023; Nature Publishing Group
• Subjects: 692/308/174; 692/699/1541/1990/804; Adult; Age; Aged; Aged, 80 and over; Biomedical and Life Sciences; Biomedicine; Bone marrow; Cancer Research; Confidence intervals; Disease Progression; Epidemiology; Female; Humans; Infectious Diseases; Informed consent; M protein; Males; Metabolic Diseases; Middle Aged; Molecular Medicine; Multiple myeloma; Multiple Myeloma - therapy; Neurosciences; Plasma cells; Precursors; Prevalence; Proteins; Risk Factors; Screening; Smoldering; Smoldering Multiple Myeloma; Iceland
• ISSN: 1078-8956; 1546-170X
• DOI: 10.1038/s41591-022-02183-6

Smoldering multiple myeloma (SMM) is an asymptomatic precursor to multiple myeloma. Here we define the epidemiological characteristics of SMM in the general population in Iceland. The iStopMM study (ClinicalTrials.gov ID:
NCT03327597
) is a nationwide screening study for multiple myeloma precursors where all residents in Iceland 40 years or older were invited to participate. SMM was defined as 10–60% bone marrow plasma cells and/or monoclonal (M) protein concentration ≥3 g dl
−1
, in the absence of myeloma-defining events. Of the 80,759 who gave informed consent to participate, 75,422 (93%) were screened. The prevalence of SMM in the total population was 0.53% (95% confidence interval (CI) = 0.49–0.57%) in individuals 40 years or older. In men and women, the prevalence of SMM was 0.67% (95% CI = 0.62–0.73%) and 0.39% (95% CI = 0.35–0.43%), respectively; it increased with age in both sexes. For the 193 individuals with SMM, median age was 70 years (range 44–92 years) and 60% were males. The mean M protein concentration of individuals with SMM was 0.62 g dl
−1
(range 0.01–3.5 g dl
−1
) and 73% had 11–20% bone marrow plasma cell infiltration. The high prevalence of SMM has implications for future treatment policies in multiple myeloma as the evidence supporting treatment initiation at the SMM stage is emerging.
A nationwide screening program from the iStopMM study performed in Iceland to detect smoldering multiple myeloma reported a prevalence of 0.5% in individuals over 40 years of age, with increasing risks with age and in males.