Author(s): Fouquet G, Guidez S, Herbaux C, Van de Wyngaert Z, Bonnet S,
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Abstract PURPOSE: Solitary plasmacytoma (SP) is a localized proliferation of monoclonal plasma cells in either bone or soft tissue, without evidence of multiple myeloma (MM), and whose prognosis is marked by a high risk of transformation to MM. EXPERIMENTAL DESIGN: We studied the impact of FDG-PET/CT (2[18F]fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography) on the risk of transformation of SP to overt MM among other markers in a series of 43 patients diagnosed with SP. RESULTS: Median age was 57.5 years; 48\% of patients had an abnormal involved serum-free light chain (sFLC) value, and 64\% had an abnormal sFLC ratio at diagnosis. Thirty-three percent had two or more hypermetabolic lesions on initial PET/CT, and 20\% had two or more focal lesions on initial MRI. With a median follow-up of 50 months, 14 patients transformed to MM with a median time (TTMM) of 71 months. The risk factors that significantly shortened TTMM at diagnosis were two or more hypermetabolic lesions on PET/CT, abnormal sFLC ratio and involved sFLC, and to a lesser extent at completion of treatment, absence of normalized involved sFLC and PET/CT or MRI. In a multivariate analysis, abnormal initial involved sFLC [OR = 10; 95\% confidence interval (CI), 1-87; P = 0.008] and PET/CT (OR = 5; 95\% CI, 0-9; P = 0.032) independently shortened TTMM. CONCLUSIONS: An abnormal involved sFLC value and the presence of at least two hypermetabolic lesions on PET/CT at diagnosis of SP were the two predictors of early evolution to myeloma in our series. This data analysis will need confirmation in a larger study, and the study of these two risk factors may lead to a different management of patients with SP in the future. . ©2014 American Association for Cancer Research.
This article was published in Clin Cancer Res
and referenced in Journal of Leukemia