Predictive value of longitudinal whole-body magnetic resonance imaging in patients with smoldering multiple myeloma

Abstract

Previous studies demonstrated the relevance of focal lesions (FL) in whole-body magnetic resonance imaging (wb-MRI) at the initial workup of patients with smoldering multiple myeloma (SMM). The aim of this study was to assess the effects of longitudinal wb-MRIs on progression into multiple myeloma (MM). Sixty-three patients with SMM were analyzed who received at least two wb-MRIs for follow-up before progression into MM. Radiological progressive disease (MRI-PD) was defined as detection of new FL or increase in diameter of existing FL and a novel or progressive diffuse infiltration. Radiological stable disease (MRI-SD) was defined by no change compared with the prior MRI. Patients were followed-up every 3-6 months, including a serological and clinical evaluation. One Hundred and eighty-two wb-MRIs were analyzed. MRI-PD occurred in 31 patients (49%), and 25 (40%) patients developed MM. MRI-PD was highly significantly associated with progression into MM, regardless of findings at the initial MRI. In multivariate analysis, MRI-PD remained a risk factor, independent of relevant baseline parameters like serum monoclonal protein or ⩾95% aberrant plasma cells in the bone marrow. Patients with MRI-SD had no higher risk of progression, even when FL were present at the initial MRI. Therefore, MRI is suitable for the follow-up of patients with SMM.

The Changing Landscape of Smoldering Multiple Myeloma: A European Perspective

“…Radiological progression was defined by the appearance of new focal lesions or a new diffuse infiltration of previously unaffected regions. Progressive disease was identified in 31 patients (49%) and was associated with a 16.5-fold risk of progression into symptomatic MM compared with patients with a stable MRI [22] It is important to note that a focal lesion on MRI reflects the presence of tumor infiltration and is insufficient for the identification of an osteolytic process. Although the results on MRI are consistent between different groups and currently incorporated in the IMWG criteria of treatmentrequiring events, standardization in interpretation and reporting of MRI results is required in subsequent studies.…”

“…A smaller study on 69 patients conducted by the Greek Myeloma Group indicated that the presence of $1 focal lesion in spine MRI was also associated with a short time to symptomatic disease (median 9 months vs. .5 years) [21]. The Heidelberg group retrospectively analyzed the outcome of 63 patients with SMM that received at least two MRIs during their follow-up [22]. Radiological progression was defined by the appearance of new focal lesions or a new diffuse infiltration of previously unaffected regions.…”

International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma

“…74,75 In the study by Hillengass, 72 diff use MRI infi ltration was associated with a HR of 3·5 (p<0·001). A 2014 analysis 76 shows that the increase in number or size of focal lesions in follow-up MRI of patients with smouldering multiple myeloma has additional predictive value, including information on growth dynamics of the plasma cell tumours in bone marrow. Therefore, in patients with diff use infi ltration, solitary focal lesion, or in the presence of equivocal fi ndings, follow-up examinations in 3-6 months are strongly recommended.…”

Diagnosis, risk stratification and management of monoclonal gammopathy of undetermined significance and smoldering multiple myeloma

“…Other factors that predict progression to symptomatic disease include abnormal plasma cell phenotype in ≥95% of cells, high plasma cell proliferative rate, hypogammaglobulinemia, gene expression profile of the purified MM cells, abnormal free lightchain ratio, increasing M-protein, presence and development of MRI abnormalities, or peripheral blood circulating plasma cells [27,43,44,[49][50][51][52][53][54]. Also, hyperdiploidy, del(17p), t(4;14), and ampl(1q) are adverse prognostic factors in SMM, independent of tumor load [55,56] (Figure 1).…”