Smoldering multiple myeloma: Integrating biology and risk into management.

Smoldering multiple myeloma (SMM) was first described over 40 years ago yet much is still unknown including which patients will ultimately progress to symptomatic multiple myeloma (MM). The genetics of the premalignant clone and the immune microenvironment in which it exists is now well understood to both play a role in disease progression. However, the clinical risk models available to help identify patients at most risk of progression still rely primarily on data reflecting volume of disease rather than underlying biology. While it is of upmost importance to accurately diagnose patients with SMM to avoid over or under treatment, efforts are ongoing to tease out if early intervention is indeed warranted for a subgroup of patients with SMM. This article will review the history and biology of SMM, discuss the utility of existing risk models, and examine the efforts to date which have challenged standard management.