Sustained Residual Disease Negativity Assessed By Diffusion-Weighted Whole-Body MRI (DW-MRI) Has Strong Predictive Relevance for Survival in Newly Diagnosed Multiple Myeloma Patients on Maintenance Therapy after Autologous Stem Cell Transplantation (ASCT)

Introduction: The role of minimal residual disease (MRD) in Multiple Myeloma (MM) as a surrogate biomarker of patients' outcome, as well as the prognostic information of functional imaging response after treatment have been established in recent years. Furthermore, the predictive relevance of sustained MRD negativity assessed by marrow and imaging techniques and its association with an excellent outcome is emerging in clinical trials. Diffusion-weighted whole-body MRI (DW-MRI) is increasingly used in the management of MM patients, but data regarding the predictive role of sustained DW-MRI response after treatment are lacking. The Myeloma Response Assessment and Diagnosis System (MY-RADS) recommendations have established criteria for Response Assessment Category (RAC) (Messiou C et al, Radiology 2019) with a 5 point scale defining the probability of complete imaging response (i.e. RAC 1) or progressive disease after treatment (i.e. RAC 5). We implemented the RAC criteria in our clinical practice and DW-MRI at 1-year in MM patients treated with autologous stem cell transplantation (ASCT) followed by maintenance therapy.