Precursor plasma cell disorders: Classification, risk stratification, and emerging role of early interception

Precursor plasma cell disorders include monoclonal gammopathy of undermined significance (MGUS) and smoldering multiple myeloma (SMM). These conditions carry a variable risk of progression to symptomatic myeloma and there are ongoing efforts to improve risk stratification to identify patients that are at highest risk of progression. Advanced imaging plays a crucial role in diagnosis and monitoring, and more sensitive tools to measure serum monoclonal proteins and circulating tumor cells are being developed. The data for early intervention in SMM continues to evolve, with several phase III studies demonstrating benefit compared to observation. There are ongoing studies evaluating the role of combination and T cell immunotherapies in patients with precursor plasma cell disorders. This review will highlight the current state of the art tools in diagnosis, risk stratification, and data for early interception in patients with precursor plasma cell dyscrasias.