Evolving changes in disease biomarkers and risk of early progression in smoldering multiple myeloma

How I manage monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is, in many ways, a unique hematologic entity. Unlike most hematologic conditions in which the diagnosis is intentional and credited to hematologists, the discovery of MGUS is most often incidental and made by nonhematologists. MGUS is considered an obligate precursor to several lymphoplasmacytic malignancies, including immunoglobulin light-chain amyloidosis, multiple myeloma, and Waldenström macroglobulinemia. Therefore, long-term follow-up is generally recommended. Despite its high prevalence, there is surprisingly limited evidence to inform best clinical practice both at the time of diagnosis and during follow-up. We present 7 vignettes to illustrate common clinical management questions that arise during the course of MGUS. Where evidence is present, we provide a concise summary of the literature and clear recommendations on management. Where evidence is lacking, we describe how we practice and provide a rationale for our approach. We also discuss the potential harms associated with MGUS diagnosis, a topic that is rarely, if ever, broached between patients and providers, or even considered in academic debate.

Smoldering Multiple Myeloma: Who and When to Treat

Smoldering multiple myeloma (SMM) is an asymptomatic plasma cell disorder characterized by the presence of ≥ 3 g/dL serum M-protein and/or 10% to 60% bone marrow plasma cell infiltration with no myeloma-defining event. The risk of progression to active multiple myeloma (MM) is not uniform, and several markers are useful for identifying patients at high risk of progression. The definition of the disease has recently been revisited and asymptomatic MMs at 80% to 90% of progression risk at 2 years are now considered to be active MM candidates for treatment. In the future, more precise biomarkers are necessary for accurate risk stratification to plan an optimized follow-up according to the risk of progression, as well as to expand the group of patients that can obtain a benefit if they receive early treatment. A phase 3, randomized trial in high-risk patients with SMM comparing early treatment versus observation has shown a significant benefit in terms of time to progression and overall survival for early intervention and confirmatory clinical trials will definitively contribute to establish the early treatment as standard of care in high-risk SMM.

Diagnosis and management of smoldering multiple myeloma: the razor's edge between clonality and cancer

Smoldering multiple myeloma (SMM) is a rare plasma cell disorder, and as the disease is asymptomatic, diagnosis is often incidental. SMM is characterized by increased marrow infiltration by clonal plasma cells and/or elevated serum M-protein in the absence of a myeloma-defining event (MDE). In recent years, SMM has gained increased attention owing to a broadening of the criteria for MDE, which include apart from the CRAB criteria, three additional parameters. Survival advantage may be offered by early treatment in the high-risk subset, based on a single trial. In this review, we assess the risk factors and models for progression to multiple myeloma. A review of our diagnostic and management approaches to SMM is presented.