The evolving pattern of the monoclonal protein improves the IMWG 2/20/20 classification for patients with smoldering multiple myeloma

The 2/20/20 International Myeloma Working Group (IMWG) score is the most employed risk score in clinical practice to evaluate the risk of progression from smoldering multiple myeloma (SMM) to symptomatic multiple myeloma. However, it faces a serious limitation: The risk score is applied at diagnosis and cannot be reapplied. Since a dynamic accurate patient risk assessment for progression is necessary, we aimed to investigate whether the detection of an evolving pattern in serum M-protein (SMP) improves the identification of high-risk patients. Eighty-three patients diagnosed with SMM between 2011 and 2020 were included. Patients were initially classified applying the 2/20/20 IMWG score at baseline and later reclassified depending on the presence of an SMP evolving pattern into six groups. We regrouped the patients into three final risk groups: low-risk, intermediate-risk, and high-risk. The risk of progression at two years for the high-risk group was 88% and all patients had progressed at 4 years. The performance measurements were superior for the new 2/20/20-Evolving score independently for the detection of high-risk patients. We show that the sequential measurement of the SMP is a noninvasive and widely available test that improves the 2/20/20 IMWG risk score.