Enhancing the R-ISS classification of newly diagnosed multiple myeloma by quantifying circulating clonal plasma cells

Am J Hematol. 2020 Mar;95(3):310-315. doi: 10.1002/ajh.25709. Epub 2020 Jan 8.


Our prior studies identified the prognostic significance of quantifying cPCs by multiparametric flow cytometry (MFC) in newly diagnosed multiple myeloma (NDMM) patients. We evaluated if a similar quantification of cPCs could add prognostic value to the current R-ISS classification of 556 consecutive NDMM patients seen at the Mayo Clinic, Rochester from 2009 to 2017. Those patients that had ≥5 cPCs/μL and either R-ISS stage I or stage II disease were re-classified as R-ISS IIB stage for the purposes of this study. The median time to next therapy (TTNT) and overall survival (OS) for patients with ≥5 cPCs/μL at diagnosis was as follows: R-ISS I (N = 110) - 40 months and not reached; R-ISS II (N = 69) - 30 and 72 months; R-ISS IIB (N = 96) - 21 and 45 months and R-ISS III (N = 281) - 20 and 47 months respectively. Finally, ≥ 5 cPCs/μL retained its adverse prognostic significance in a multivariable model for TTNT and OS. Hence, quantifying cPCs by MFC can potentially enhance the R-ISS classification of a subset of NDMM patients with stage I and II disease by identifying those patients with a worse than expected survival outcome.

Publication types

  • Clinical Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Disease-Free Survival
  • Female
  • Flow Cytometry*
  • Humans
  • Male
  • Middle Aged
  • Multiple Myeloma* / blood
  • Multiple Myeloma* / diagnosis
  • Multiple Myeloma* / mortality
  • Multiple Myeloma* / therapy
  • Neoplasm Staging
  • Plasma Cells / metabolism*
  • Plasma Cells / pathology
  • Retrospective Studies
  • Survival Rate