Smoldering multiple myeloma.

Smoldering multiple myeloma (SMM) is an asymptomatic clonal plasma cell disorder. SMM is distinguished from monoclonal gammopathy of undetermined significance by a much higher risk of progression to multiple myeloma (MM). There have been major advances in the diagnosis, prognosis, and management of SMM in the last few years. These include a revised disease definition, identification of several new prognostic factors, a classification based on underlying cytogenetic changes, and new treatment options. Importantly, a subset of patients previously considered SMM is now reclassified as MM on the basis of biomarkers identifying patients with an ≥80% risk of progression within 2 years. SMM has assumed greater significance on the basis of recent trials showing that early therapy can be potentially beneficial to patients. As a result, there is a need to accurately diagnose and risk-stratify patients with SMM, including routine incorporation of modern imaging and laboratory techniques. In this review, we outline current concepts in diagnosis and risk stratification of SMM, and provide specific recommendations on the management of SMM.