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    Plasma Cell precursor and Other Disorders

    Category: Plasma Cell precursor and Other Disorders

    Diffuse bone marrow activity as prognostic biomarker in patients with smouldering Multiple Myeloma

    (PA-359) Diffuse Bone Marrow Activity as Prognostic Biomarker in Patients with Smouldering Multiple Myeloma

    Wednesday, September 17, 2025

    • Gianluca Maiorana

      PhD Student
      Hematology Unit, Sant'Andrea University Hospital, Department of Clinical and Molecular Medicine, La Sapienza University, Rome

    Introduction: Smouldering Multiple Myeloma (sMM) is an asymptomatic plasma cell disorder with a variable yet significant risk of progression to symptomatic Multiple Myeloma (MM). Current prognostic models help stratify patients into risk categories but often lack dynamic markers that reflect ongoing disease biology. Diffuse marrow activity (DMA), a radiological finding observable via Whole Body MRI (WBMRI) and PET/CT, has been proposed as a potential imaging biomarker, though its role in risk prediction remains under-explored in real-world sMM populations diagnosed with modern IMWG criteria. The aim of this study was the evaluation of DMA as prognostic marker in sMM

    Methods:

    This retrospective monocentric study enrolled 80 patients diagnosed with sMM between 2014 and 2025 according to the IMWG criteria. Patients underwent WBMRI (including DWI sequences) and/or PET/CT at baseline. DMA was defined as an ADC value of 550-650 μm²/s on WBMRI or a Deauville score of 2–3 on PET/CT. Prognostic stratification was performed using 20/20/2, IMWG high-precision (with FISH), and PANGEA scores at diagnosis and last follow-up. Statistical analysis was conducted using SPSS v29.0

    Results: DMA was detected in 43% of patients overall, with higher sensitivity observed in WBMRI (71%) compared to PET/CT (29%). Eighteen patients (22%) progressed to MM over a median follow-up of 20 months (range: 3–111), with a median TTP of 29.5 months. Among those who progressed, 72% had DMA at baseline. Patients with DMA had a shorter TTP (24 vs. 38 months). Even among patients classified as low or intermediate risk by all three scores, those with positive imaging had significantly shorter TTP (26 months). A statistically significant correlation was found between DMA presence and progression (p = 0.01), as well as between DMA and increases in prognostic scores or sFLC ratio during follow-up (p = 0.02–0.05). Among non-progressors with follow-up > 20 months, patients with DMA showed a statistically significant increase in sFLC ratio and PANGEA score over time, suggesting a dynamic evolution despite initial low-risk classification

    Conclusions:

    This study supports the role of diffuse marrow activity (DMA) as an independent and dynamic biomarker of progression risk in sMM. Imaging findings correlated with established risk scores and predicted earlier progression, even in patients initially stratified as low or intermediate risk. WBMRI demonstrated superior sensitivity in detecting DMA, while PET/CT proved valuable for confirming metabolic activity. The sequential use of both modalities enhanced diagnostic accuracy. These findings advocate for the integration of DMA into future risk models and suggest WBMRI as a preferred first-line imaging tool in centers where available. Prospective studies on larger cohorts are warranted to validate these observations and refine risk-adapted management strategies. A multicentric prospective study will shortly enroll patients with sMM to evaluate the prognostic impact of DMA