Association of loss of spleen visualization on whole-body diffusion-weighted imaging with prognosis and tumor burden in patients with multiple myeloma

Abstract

This study investigated the clinical significance of loss of spleen visualization (LSV) on whole-body diffusion-weighted imaging (WB-DWI) in patients with multiple myeloma (MM). The WB-DWI of 96 patients with newly diagnosed MM (NDMM) and 15 patients with smoldering MM (sMM) were retrospectively reviewed. LSV was observed in 56 patients with NDMM (58.3%) and 1 patient with sMM (6.7%). Patients with NDMM with LSV had a higher median infiltration of bone marrow plasma cells (80.0% vs. 50.0%, p < 0.001) and median total diffusion volume (median; 540.2 vs. 137.0 mL, p = 0.003) than patients without LSV. Patients with LSV had a lower spleen-to-spinal cord ratio (0.36 vs. 0.96, p < 0.001) and worse 2-year overall survival (OS) (84.6% vs. 100%, p = 0.032). Patients who did not recover spleen visualization during treatment had a worse prognosis, even when they obtained very good partial response (median progression-free survival: 13.2 months). Spleen histopathological findings revealed higher cellularity and diffuse myeloma cell infiltration in a patient with LSV and splenic amyloidosis without extramedullary hematopoiesis in a patient without LSV. Therefore, LSV indicates worse prognosis for patients with MM, even when the patient responds to treatment. Further studies are warranted to clarify the immunological role of spleen in MM.

Reduced splenic uptake on 68Ga-Pentixafor-PET/CT imaging in multiple myeloma - a potential imaging biomarker for disease prognosis

“…This was questioned by a recent Japanese study of 96 NDMM patients investigating the clinical significance of loss of spleen visualization on DW-MRI. They could also show that loss of spleen visualization is associated with high tumor burden and poor prognosis [35]. In our cohort of pre-treated MM patients, we were able to corroborate these MRI findings with 68 Ga-Pentixafor uptake of the spleen being negatively associated with ISS stage at the time point of PET imaging, percentage of malignant plasma cells in the bone marrow as well as presence of extramedullary disease at the time point of PET imaging.…”

“…Reduced splenic 68 Ga-Pentixafor uptake is associated with advanced disease stage and bone marrow insufficiency Differences in spleen CXCR4 expression as visualized by 68 Ga-Pentixafor-PET/CT could potentially be associated with tumor burden and hematopoietic reserve, as this was reported in previous studies investigating the spleen signal using MRI [34,35]. In detail, we investigated whether splenic uptake was associated with ISS, presence of extramedullary disease (EMD), or the number of focal lesions.…”

“…In this context, Rasche et al demonstrated the spleen signal in diffusion-weighted magnetic resonance imaging (DW-MRI) to be associated with tumor burden and prognosis in 295 newly diagnosed MM (NDMM) patients [34]. Recently, this observation was confirmed in a Japanese study with 96 patients, reporting that loss of spleen visualization on DW-MRI imaging correlates with high tumor volume and poor prognosis [35]. Interestingly, heterogeneous splenic 68 Ga-Pentixafor uptake could also be observed in MM patients.…”