What is the prognosis of solitary bone plasmacytoma (SBP)?

Updated: Mar 10, 2021
  • Author: Suzanne R Fanning, DO; Chief Editor: Emmanuel C Besa, MD  more...
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Solitary bone plasmacytoma (SBP) progresses to multiple myeloma at a rate of 65-84% at 10 years and 65-100% at 15 years. The median onset of conversion to multiple myeloma is 2-5 years with a 10-year disease-free survival rate of 15-46%. The overall median survival time is 10 years. [14]

Kyle described the following 3 patterns of treatment failure [18] :

  • Development of multiple myeloma (54%)
  • Local recurrence (11%)
  • Development of new bone lesions in the absence of multiple myeloma (2%)

Prognostic features for conversion of  SBP to multiple myeloma, although controversial, include the following [19, 20, 21] :

  • Lesion size of at least 5 cm
  • Patient age 40 years and older
  • High M protein levels
  • Persistence of M protein after treatment
  • Spine lesions

In a study by Wilder et al, 10-year myeloma-free survival in patients whose M protein resolved within 1 year after radiation therapy was 91%, versus 29% in patients whose M-protein persisted beyond that time. [22]

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