Structured whole-body MRI highlights clinically relevant disease pattern changes in relapsed/refractory multiple myeloma

Whole-body imaging plays a critical role in assessing multiple myeloma (MM). The structured scoring systems MY-RADS and KIM score have primarily been developed for newly diagnosed patients (NDMM). However, their application and prognostic significance in relapsed/refractory multiple myeloma (RRMM) remains uncertain. To clarify this, we evaluated whole body magnetic resonance imaging (MRI) data from 46 RRMM patients and compared findings to 68 NDMM patients from the GMMG-HD7 trial using both scoring systems. Despite similar overall disease burden, RRMM patients showed significant differences, characterized by increased paramedullary and extramedullary disease and reduced diffuse marrow infiltration compared to NDMM. Both MY-RADS and KIM scores independently correlated with progression-free and overall survival in RRMM. These results highlight distinct biological patterns in RRMM, emphasizing a shift towards bone marrow-independent growth. Our findings suggest that in RRMM, iliac crest biopsies may underestimate disease burden, underlining the importance of imaging complementing bone marrow diagnostics.