Smoldering multiple myeloma: to treat or not to treat.

Introduction: Smoldering multiple myeloma (SMM) is an asymptomatic disorder characterized by the presence of ≥ 30 g/l serum M-protein and/or ≥ 10% bone marrow plasma cell infiltration. The progression risk to active multiple myeloma (MM) is not uniform, and several prognostic parameters are useful for identifying patients at high risk of progression. A watch-and-wait approach has been the standard of care up to now. However, recently, it has been demonstrated that a subset of high-risk cases can benefit from early treatment with new drugs.
Areas Covered: In this editorial, we focus on SMM and evaluate the diagnostic work-up and the prognostic factors predicting progression to symptomatic MM. We also review the studies in which the role of early treatment has been evaluated for patients with SMM.
Expert Opinion: After the update performed by the International Myeloma Working Group regarding MM diagnosis, it is now time to change the therapeutic paradigm for this disease. While "ultra high-risk" myeloma should now be considered as active MM, for low-risk patients the "watch-and-wait" strategy is still recommended. More caution is needed for the high-risk group: physicians should continue monitoring patients using every tool now available while waiting for results from ongoing trials that will establish if this group will benefit from an early intervention.