Determining the clinical significance of monoclonal gammopathy of undetermined significance: a SEER-Medicare population analysis

Diagnosis and Management of Monoclonal Gammopathy of Undetermined Significance: A Review

Importance

Nearly 5% of adults have the precursor malignant condition monoclonal gammopathy of unknown significance (MGUS). Management centers on differentiating MGUS from more serious conditions to determine additional diagnostic testing, monitoring, and potential therapy.

Observations

MGUS is defined by the absence of end-organ damage or symptoms, a small amount of monoclonal immunoglobulin (M protein), and low volume of plasma cells. MGUS must be distinguished from overt malignant diseases like multiple myeloma (MM), immunoglobulin light-chain (AL) amyloidosis, and monoclonal gammopathy of clinical significance (MGCS), all of which cause organ damage or symptoms. Although testing for M proteins is often prompted by clinical findings (eg, osteoporosis or autoimmune disease), recent evidence from screened populations suggests that previous MGUS disease associations were likely overestimated and that testing for M proteins should be reserved for when malignant disease or MGCS is suspected. Risk of progression to malignant disease ranges from 0.5% to 1%, meaning most patients have indolent disease. Guideline-concordant management of MGUS is determined by predicted risk of progression to malignant disease, which depends on subtype of immunoglobulin, M protein concentration, and free light chain ratio. Patients with low-risk MGUS can safely defer bone marrow biopsy and advanced imaging, and should undergo periodic laboratory monitoring. Intermediate- and high-risk MGUS should trigger bone marrow biopsy and bone imaging to detect overt MM and shorter monitoring intervals. Advanced molecular testing may improve on current risk stratification to target monitoring and treatment to those with highest risk of malignant progression and avoid overtreatment of those with low-risk disease. Management will also be informed by results of several clinical trials to clarify the risks and benefits of screening, optimal monitoring strategy, predictors of progression, and potential preventive or curative therapies.

Conclusions and Relevance

Evidence-based management of MGUS currently rests on separating clinically indolent from high-risk precursor disease. Research using novel detection methods, incorporating molecular testing into risk stratification, and evaluating screening, monitoring, and therapeutic or lifestyle interventions has the potential to improve outcomes.

[Expert consensus on the comprehensive management of monoclonal gammopathy of undetermined significance and smoldering multiple myeloma in China (2025)]

Monoclonal gammopathy of undetermined significance (MGUS) is the most common type of plasma cell disorder, characterized by clonal proliferation of plasma cells in the bone marrow, a mild increase in monoclonal protein (M protein), and no organ damage. Smoldering multiple myeloma (SMM) is a plasma cell disease that lies between MGUS and active multiple myeloma (AMM), featuring elevated levels of M protein in the plasma and increased plasma cell infiltration in the bone marrow, but without typical clinical manifestations. SMM is considered as a precursor state to AMM. This consensus was jointly developed by the Plasma Cell Disease Group, Chinese Society of Hematology, Chinese Medical Association and the Chinese Myeloma Committee-Chinese Hematology Association, covering the epidemiological characteristics, clinical manifestations, testing and examination, diagnostic criteria, differential diagnosis, prognosis assessment, and patient management strategies for MGUS and SMM. The consensus aims to provide standardized guidance for the comprehensive management of MGUS and SMM, ensuring timely monitoring of disease progression and intervention at the appropriate time to improve the quality of life and survival rates of patients.

Comparison of progression risk of monoclonal gammopathy of undetermined significance by method of detection

ABSTRACT

Monoclonal gammopathy of undetermined significance (MGUS) is an asymptomatic premalignant disorder. The current standard of care is not to screen for MGUS, so it is often incidentally diagnosed in the clinic. It is unknown whether the outcomes of screened vs clinically detected MGUS differ. We compared the progression risk between screened vs clinical MGUS cohorts and assessed whether the MGUS detection method affected risk prediction of established clinical factors (score). We included 379 screened MGUS cases from the Olmsted County population-based study and 1384 patients with MGUS diagnosed during routine clinical evaluation at Mayo Clinic. Median follow-up time for the screened vs clinical cohort was 26.6 and 40.1 years, respectively. Accounting for death as a competing risk, the cumulative incidence of progression at 25 years was similar in the screened (11.1% [95% confidence interval [CI], 8.3-14.8]) vs clinical (10.1% [95% CI, 8.6-11.8]) MGUS cohorts, even when stratified by sex, age, or the baseline MGUS risk score. Overall, 0.9 (95% CI, 0.6-1.2) of patients with screened MGUS vs 1.0 (95% CI, 0.9-1.2) of those with clinically detected MGUS experienced disease progression for every 100 person-years of follow-up. MGUS detection method did not modify the association between MGUS risk score and progression risk (pinteraction = 0.217) and did not add to known risk factors for progression (likelihood ratio test; P = .839). Here, we show that progression risk among patients with screened vs clinically detected heavy-chain MGUS was similar. Future studies are needed to assess whether tailored follow-up of patients with screened MGUS affects clinical outcomes.

The role of nutrition and gut microbiome in the progression of multiple myeloma and its precursor disease

Multiple myeloma (MM) is the second most common hematological malignancy, characterized by unregulated monoclonal proliferation in the bone marrow. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are premalignant conditions that can progress to MM. Identifying etiological risk factors for MM and its precursor diseases is crucial for prevention. Obesity, diet, vitamin D levels, and gut microbiota alterations have been identified as lifestyle factors affecting MM and MGUS risk. Upon disease onset, treatment strategies aim to reduce disease burden, enhance prognosis, and optimize patients' quality of life. Nutrition and body weight have been shown to affect disease progression and treatment outcomes. MM patients often present with vitamin D, vitamin B12, and folate deficiencies, which worsen disease prognosis. High body mass index is linked to increased death rates among MM patients and an increased risk of MGUS transformation to MM. Gut microbiota has also been associated with disease progression and response to treatment. This literature review aims to summarize the available evidence regarding the impact of nutrition and nutritional status on MM patients beyond prevention, highlighting the significance of gut microbiome and dysbiosis in MM progression.

SOHO State of the Art Updates and Next Questions: Diagnosis and Management of Monoclonal Gammopathy of Undetermined Significance and Smoldering Multiple Myeloma

Monoclonal proteins are common, with a prevalence in the United States around 5% and the incidence increases with age. Although most patients are asymptomatic, the vast majority of cases are caused by a clonal plasma cell disorder. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic precursor conditions with variable risk of progression to multiple myeloma (MM). In recent years, significant progress has been made to better understand the factors that lead to the development of symptoms and progression to myeloma. In this review, we summarize the current diagnosis treatment guidelines for MGUS and SMM and highlight recent advances that underscore a shifting paradigm in the evaluation and management of plasma cell precursor conditions.

Clinical significance of FLC tests in patients without other evidence of hematologic disorder

The clinical significance of an abnormal free light chain (FLC) test, performed due to unspecific complains in the absence of a known plasma cell dyscrasia (PCD) or lymphoproliferative disease (LPD), is not fully elucidated. We investigated the importance of an abnormal FLC ratio (FLC-R) in this setting. Patients registered in the Maccabi Healthcare Services database, tested for FLC during 2007-2023 without previously documented PCD/LPD or increased total protein (TP) level, were reviewed. Demographics, co-morbidities, and laboratory tests were recorded. FLC-R was defined as normal (0.26-1.65) or slightly (slAb 0.1-0.26/1.65-4), moderately (mAbn 0.1-0.05/4-8) and significantly abnormal (sigAb- < 0.05 or > 8). Factors associated with PCD/LPD and overall survival were identified. In total, 8,661 patients, 2,215 (25.6%) with abnormal FLC-R [2,090 (24.1%)-slAb, 65 (0.75%)-mAbn and 60 (0.7%)-sigAb], were analyzed. Almost none had anemia nor acute renal failure. 14% had concomitant increased immunoglobulins. Within a median follow-up of 52 months, 943 were diagnosed with PCD (816-MGUS, 127-MM/Amyloidosis/plasmacytoma) and 48 with LPD. Median time to PCD and LPD were 19 and 28 months. Multivariate analysis found slAb (HR = 1.8, CI95%:1.53-2.12, p < 0.001), mAbn (HR = 6.3, CI95%:4.16-9.53, p < 0.001), and sigAb FLC (HR = 10.4, CI95%:7.0-15.35, p < 0.001), to be associated with PCD/LPD diagnosis. Decreased IgG, increased IgA, and concomitant comorbidities predicted PCD, whereas increased IgM predicted LPD. Older age, male gender, anemia, decreased albumin, increased IgG and concomitant comorbidities, predicted shorter survival. Our large study emphasizes the independent clinical significance of abnormal FLC-R as a predictor of PCD/LPD diagnosis even in patients with normal TP level, promoting early detection of PCD/LPD.

Multiple myeloma incidence and mortality trends in the United States, 1999-2020

Multiple myeloma (MM) is a plasma cell disorder accounting for approximately 10% of hematologic malignancies. There is limited epidemiological evidence regarding the long-term trends and disparities in MM in the US. We conducted a multiple time point cross-sectional study using MM incidence rate data from the Surveillance, Epidemiology, and End Results (SEER) database and mortality data from the CDC Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) Underlying Cause of Death database between 1999 and 2020. During this period, MM incidence has steadily increased, while MM mortality has steadily decreased, with substantial racial and ethnic disparities. Non-Hispanic Black individuals exhibited the highest incidence rates, which consistently rose from 12.02 (95% CI 10.54, 13.64) in 1999 to 14.20 (95% CI 12.93, 15.55) per 100,000 population by 2020. Non-Hispanic American Indian/Native Alaskans and Asian/Pacific Islanders demonstrated the lowest incidence rates of 5.59 (95% CI 2.69, 10.04) and 3.56 (95% CI 2.94, 4.27) per 100,000 population in 1999 to 5.76 (95% CI 3.49, 8.90) and 3.92 (95% CI 3.46, 4.42) per 100,000 population, respectively, by 2020. Disparities by gender, age, US census region, and rurality were observed, underscoring the importance of targeted, equity-centered interventions and MM screening initiatives for at-risk populations.

Discrepant serum creatinine concentrations caused by paraprotein interference preceding diagnosis of monoclonal gammopathy of undetermined significance

We report a man in his 70s who presented with discrepant serum creatinine concentrations in different hospitals at the same time. Further examinations of these discrepancies revealed turbidity of the serum sample and, thus, a reagent reaction and false hypercreatinine caused by paraprotein interference were suspected. Serum protein electrophoresis revealed a small amount of monoclonal γ globulin (2.9 g/L), which may have been involved in paraprotein interference. Monoclonal λ-type IgG was detected in the serum, resulting in a diagnosis of monoclonal gammopathy of undetermined significance. Previous studies indicated paraprotein interference in serum containing monoclonal IgM or a large amount of IgG (> 25 g/L). Although this case of paraprotein interference induced by a small amount of IgG is rare, a discrepancy in creatinine results may be an indicator leading to the diagnosis of plasma cell proliferative diseases.

Development of a Multivariable Model to Predict the Need for Bone Marrow Sampling in Persons With Monoclonal Gammopathy of Undetermined Significance : A Cohort Study Nested in a Clinical Trial

BACKGROUND

Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic precursor conditions to multiple myeloma and related disorders. Smoldering multiple myeloma is distinguished from MGUS by 10% or greater bone marrow plasma cells (BMPC) on sampling, has a higher risk for progression, and requires specialist management.

OBJECTIVE

To develop a multivariable prediction model that predicts the probability that a person with presumed MGUS has 10% or greater BMPC (SMM or worse by bone marrow criteria) to inform the decision to obtain a bone marrow sample and compare its performance to the Mayo Clinic risk stratification model.

DESIGN

iStopMM (Iceland Screens, Treats or Prevents Multiple Myeloma), a prospective population-based screening study of MGUS. (ClinicalTrials.gov: NCT03327597).

SETTING

Icelandic population of adults aged 40 years or older.

PATIENTS

1043 persons with IgG, IgA, light-chain, and biclonal MGUS detected by screening and an interpretable bone marrow sample.

MEASUREMENTS

Monoclonal gammopathy of undetermined significance isotype; monoclonal protein concentration; free light-chain ratio; and total IgG, IgM, and IgA concentrations were used as predictors. Bone marrow plasma cells were categorized as 0% to 4%, 5% to 9%, 10% to 14%, or 15% or greater.

RESULTS

The c-statistic for SMM or worse was 0.85 (95% CI, 0.82 to 0.88), and calibration was excellent (intercept, -0.07; slope, 0.95). At a threshold of 10% predicted risk for SMM or worse, sensitivity was 86%, specificity was 67%, positive predictive value was 32%, and negative predictive value was 96%. Compared with the Mayo Clinic model, the net benefit for the decision to refer for sampling was between 0.13 and 0.30 higher over a range of plausible low-risk thresholds.

LIMITATION

The prediction model will require external validation.

CONCLUSION

This accurate prediction model for SMM or worse was developed in a population-based cohort of persons with presumed MGUS and may be used to defer bone marrow sampling and referral to hematology.

PRIMARY FUNDING SOURCE

International Myeloma Foundation and the European Research Council.

Laboratory practice is central to earlier myeloma diagnosis: Utilizing a primary care diagnostic tool and laboratory guidelines integrated into haematology services

Treatment advances have greatly improved survival, but myeloma is among the worst of all cancers for delayed diagnosis, causing serious morbidities and early deaths. This delay is largely because the symptom profile of myeloma has very low specificity, and in primary care, myeloma is rare. However, initiating the journey to diagnosis simply requires considering myeloma and sending blood to test for monoclonal immunoglobulin. Laboratory tests reliably detect monoclonal immunoglobulin, which is present in 99% of myeloma cases, so why do health care systems have such a problem with delayed diagnosis? The Myeloma UK early diagnosis programme has brought together diverse expertise to investigate this problem, and this article was prepared by the programme's working group for laboratory best practice. It reviews evidence for test requesting, analysis and reporting, for which there is large variation in practice across the United Kingdom. It presents a 'GP Myeloma diagnostic tool' and how it can be integrated into laboratory practice alongside a laboratory best practice tool. It proposes improved requesting and integration with haematology services for reporting and interpretation. Here the laboratory has a central role in creating efficient and cost-effective pathways for appropriate and timely bone marrow examination for myeloma diagnosis.

Screening in Multiple Myeloma and Its Precursors: Are We There Yet?

BACKGROUND

Multiple myeloma (MM) is a hematological malignancy that develops over years from the asymptomatic precursors, monoclonal gammopathy of undetermined significance, and smoldering multiple myeloma. Recent evidence shows that by initiating treatment at an asymptomatic stage, outcomes in MM can be significantly improved. However, a vast majority of MM patients are diagnosed after the development of symptomatic end-organ damage and cannot reap the benefits of early treatment. The precursors of MM are easily detected by serum protein electrophoresis and free light chain assay of the serum, raising the question of whether population-based screening could detect MM at an asymptomatic stage and significantly expand the availability of early treatment in MM. Screening is a hallmark of care in many malignancies, and there are accepted criteria for when screening is appropriate.

CONTENT

Here we review the available relevant evidence for the introduction of screening and discuss whether screening for MM and its precursors fulfills these criteria. We also highlight gaps in our current knowledge, most notably a lack of data on the benefits and harms of screening and the lack of a defined target population. There are ongoing studies that may fill these critical gaps in the literature, but their results are still pending.

SUMMARY

Screening could lead to a paradigm shift in the care of patients with MM, but critical scientific questions need to be answered before screening of healthy individuals can be recommended. In short, we should not screen for MM and its precursors-yet.

Machine Learning Approach for Rapid, Accurate Point-of-Care Prediction of M-Spike Values in Multiple Myeloma

PURPOSE

The gold standard for monitoring response status in patients with multiple myeloma (MM) is serum and urine protein electrophoresis which quantify M-spike proteins; however, the turnaround time for results is 3-7 days which delays treatment decisions. We hypothesized that machine learning (ML) could integrate readily available clinical and laboratory data to rapidly and accurately predict patient M-spike values.

METHODS

A retrospective chart review was performed using the deidentified, electronic medical records of 171 patients with MM.

RESULTS

Random forest (RF) analysis identified the weighted value of each independent variable (N = 43) integrated into the ML algorithm. Pearson and Spearman coefficients indicated that the ML-predicted M-spike values correlated highly with laboratory-measured serum protein electrophoresis values. Feature selected RF modeling revealed that only two variables-the first lagged M-spike and serum total protein-accurately predicted the M-spike.

CONCLUSION

Taken together, our results demonstrate the feasibility and prognostic potential of ML tools that integrate electronic data to longitudinally monitor disease burden. ML tools support the seamless, secure exchange of patient information to expedite and personalize clinical decision making and overcome geographic, financial, and social barriers that currently limit the access of underserved populations to cancer care specialists so that the benefits of medical progress are not limited to selected groups.

Investigation and management of the monoclonal gammopathy of undetermined significance: A British Society for Haematology Good Practice Paper

This Good Practice Paper provides recommendations for the diagnosis, risk stratification and management of the monoclonal gammopathy of undetermined significance (MGUS). It describes the recently recognised entity of the monoclonal gammopathy of clinical significance (MGCS), and recommends how it should be managed. The potential for targeted population screening for MGUS is also discussed.

Presenting Symptoms in Newly Diagnosed Myeloma, Relation to Organ Damage, and Implications for Symptom-Directed Screening: A Secondary Analysis from the Tackling Early Morbidity and Mortality in Myeloma (TEAMM) Trial

Multiple myeloma (MM) patients risk diagnostic delays and irreversible organ damage. In those with newly diagnosed myeloma, we explored the presenting symptoms to identify early signals of MM and their relationships to organ damage. The symptoms were recorded in patients' own words at diagnosis and included diagnostic time intervals. Those seen by a haematologist >6 months prior to MM diagnosis were classified as precursor disease (PD). Most (962/977) patients provided data. Back pain (38%), other pain (31%) and systemic symptoms (28%) predominated. Patients rarely complain of 'bone pain', simply 'pain'. Vertebral fractures are under-recognised as pathological and are the predominant irreversible organ damage (27% of patients), impacting the performance status (PS) and associated with back pain (odds ratio (OR) 6.14 [CI 4.47-8.44]), bone disease (OR 3.71 [CI 1.88-7.32]) and age >65 years (OR 1.58 [CI 1.15-2.17]). Renal failure is less frequent and associated with gastrointestinal symptoms (OR 2.23 [CI1.28-3.91]), age >65 years (OR 2.14 [CI1.28-3.91]) and absence of back pain (OR 0.44 [CI 0.29-0.67]). Patients with known PD (n = 149) had fewer vertebral fractures (p = 0.001), fewer adverse features (p = 0.001), less decline in PS (p = 0.001) and a lower stage (p = 0.04) than 813 with de novo MM. Our data suggest subgroups suitable for trials of 'symptom-directed' screening: those with back pain, unexplained pain, a general decline in health or low-impact vertebral compression fractures.

Monoclonal gammopathy of increasing significance: time to screen?

Monoclonal gammopathy (MG) is a frequently detected clonal B-cell or plasma-cell disorder. Importantly, every multiple myeloma (MM) case is preceded by MG. Although clinical algorithms now allow earlier treatment of patients with biomarkers of malignancy before MM-induced tissue damage (CRAB) occurs, most patients are still diagnosed late. It is important to revisit how MG should be managed in clinical practice and whether screening is required. As the prevalence of MG and other medical co-morbidities both rise with increasing age, the degree of contribution of MG to disease states other than malignant progression is often unclear. This can lead to monitoring lapses and under recognition of the organ dysfunction that can occur with monoclonal gammopathy of clinical significance (MGCS). Therefore, models of progression to MM and/or MGCS require further refinement. While MG is currently detected incidentally, a case for screening has been made with ongoing studies in this area. Screening has the potential benefit of earlier detection and prevention of both MGCS and delayed MM presentations, but important drawbacks include the psychosocial impact on individuals and resource burden on healthcare services. MG terminology should transition alongside our increasing understanding of the condition and genomic characterization that have already begun to revise the MG nomenclature. The biology of MG has been poorly understood and is often inferred from the biology of MM, which is unhelpful. We review the literature and case for MG screening in this paper. In particular, we highlight areas that require focus to establish screening for MG.

Patient and provider-level drivers of healthcare utilization related to a diagnosis of a precancerous condition: monoclonal gammopathy of undetermined significance (MGUS)

PURPOSE

Monoclonal gammopathy of undetermined significance (MGUS) is the precursor of multiple myeloma. This qualitative study described patient (n = 14) experiences and healthcare providers' (n = 8) opinions and practices concerning care for patients with MGUS in the US.

METHODS

Semi-structured, in-depth interviews were analyzed using thematic analysis.

RESULTS

We identified six overarching themes related to the care pathway for patients with MGUS: (1) Process of MGUS diagnosis, (2) Providers' explanations, (3) Patients' understanding, (4) Impact of the diagnosis, (5) Follow-up/management, and (6) Factors influencing healthcare utilization. Patients demonstrated a basic understanding of MGUS. However, some patients felt anxiety around the diagnosis, which may affect other aspects of their lives. Non-hematologist providers report having less MGUS-specific knowledge. Older age, high-risk MGUS, and insurance coverage/healthcare costs influenced healthcare utilization.

CONCLUSION

Patients with MGUS may have difficulty processing this premalignant diagnosis. Non-hematologist providers may have gaps in knowledge around specific care for patients with MGUS.

Prevalence of smoldering multiple myeloma based on nationwide screening

Smoldering multiple myeloma (SMM) is an asymptomatic precursor to multiple myeloma. Here we define the epidemiological characteristics of SMM in the general population in Iceland. The iStopMM study (ClinicalTrials.gov ID: NCT03327597 ) is a nationwide screening study for multiple myeloma precursors where all residents in Iceland 40 years or older were invited to participate. SMM was defined as 10-60% bone marrow plasma cells and/or monoclonal (M) protein concentration ≥3 g dl-1, in the absence of myeloma-defining events. Of the 80,759 who gave informed consent to participate, 75,422 (93%) were screened. The prevalence of SMM in the total population was 0.53% (95% confidence interval (CI) = 0.49-0.57%) in individuals 40 years or older. In men and women, the prevalence of SMM was 0.67% (95% CI = 0.62-0.73%) and 0.39% (95% CI = 0.35-0.43%), respectively; it increased with age in both sexes. For the 193 individuals with SMM, median age was 70 years (range 44-92 years) and 60% were males. The mean M protein concentration of individuals with SMM was 0.62 g dl-1 (range 0.01-3.5 g dl-1) and 73% had 11-20% bone marrow plasma cell infiltration. The high prevalence of SMM has implications for future treatment policies in multiple myeloma as the evidence supporting treatment initiation at the SMM stage is emerging.

The consultant's guide to smoldering multiple myeloma

Smoldering multiple myeloma (SMM) is an asymptomatic precursor condition to multiple myeloma (MM). The prevalence of SMM is 0.5% in persons over 40 years old; it is higher in men than women and increases with age. When SMM is diagnosed, a thorough diagnostic workup is necessary to exclude myeloma-defining events and stratify patients according to risk of progression to MM. While close monitoring for progression remains the best management for most patients with SMM, in this article, we discuss if treatment initiation before myeloma-defining events occur might be relevant in selected high-risk cases. Two randomized clinical trials have shown a clinical benefit of initiating treatment at the SMM stage, whereof 1 showed an overall survival benefit for those receiving treatment. We discuss various risk stratification models in SMM, important treatment trials, and ongoing trials. Finally, we present how to approach the clinical management of patients with SMM.

Monoclonal Gammopathies of Clinical Significance: A Critical Appraisal

Monoclonal gammopathies of clinical significance (MGCSs) represent a group of diseases featuring the association of a nonmalignant B cells or plasma cells clone, the production of an M-protein, and singularly, the existence of organ damage. They present a current framework that is difficult to approach from a practical clinical perspective. Several points should be addressed in order to move further toward a better understanding. Overall, these entities are only partially included in the international classifications of diseases. Its definition and classification remain ambiguous. Remarkably, its real incidence is unknown, provided that a diagnostic biopsy is mandatory in most cases. In fact, amyloidosis AL is the final diagnosis in a large percentage of patients with renal significance. On the other hand, many of these young entities are syndromes that are based on a dynamic set of diagnostic criteria, challenging a timely diagnosis. Moreover, a specific risk score for progression is lacking. Despite the key role of the clinical laboratory in the diagnosis and prognosis of these patients, information about laboratory biomarkers is limited. Besides, the evidence accumulated for many of these entities is scarce. Hence, national and international registries are stimulated. In particular, IgM MGCS deserves special attention. Until now, therapy is far from being standardized, and it should be planned on a risk and patient-adapted basis. Finally, a comprehensive and coordinated multidisciplinary approach is needed, and specific clinical trials are encouraged.

Multi-trajectory models of serum biomarkers among patients with monoclonal gammopathy of undetermined significance

Understanding the progression of monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM) is needed to identify patients who would benefit from closer clinical surveillance. Given that two of the defining criteria of MM are renal failure and anemia, we described the trajectories of creatinine (Cr) and hemoglobin (Hgb) over time in patients with a diagnosis of MGUS. Patients diagnosed with MGUS (n = 424) were identified by a previously validated case-finding algorithm using health claims and electronic health record data (2007-2015) and followed through 2018. Group-based trajectory modeling identified patients with distinct laboratory value trajectories of Cr (mg/dl) and Hgb (g/dl). Most patients were non-Hispanic White (97.6%) with a mean age of 75 years at MGUS diagnosis. Three multi-trajectory groups were identified: (1) Normal Cr/Hgb (n = 225; 53.1%)-stable serum Cr levels and decreasing, normal Hgb levels; (2) Normal Cr/lower-normal Hgb group (n = 188; 44.3%)-stable, slightly elevated levels of Cr and decreasing levels of Hgb; and (3) High Cr/borderline Hgb group (n = 11; 2.6%)-increased Cr levels and stable low levels of Hgb. Patients with MGUS in Group 2 were older than patients in other groups, and patients in group 3 had more comorbidities than participants in all other groups. Few patients developed MM during the study period. We were able to identify distinct biomarker trajectories in patients with MGUS over time. Future research should investigate how these trajectories may be related to the risk of progression to MM, including M-protein levels.

Differences in Hospital, Emergency Room and Outpatient Visits Among Adults With and Without Monoclonal Gammopathy of Undetermined Significance

INTRODUCTION

This study evaluated the impact of receiving a monoclonal gammopathy of undetermined significance (MGUS) diagnosis on healthcare utilization from patients at a community-based multispecialty provider organization.

METHODS

A cohort of patients with MGUS (n = 429) were matched on sex, age, and length of enrollment to a cohort of patients without MGUS (n = 1286). Healthcare utilization was assessed: 1-12 months before, 1 month before and after, and 1-12 months after diagnosis/index date. Multivariable conditional Poisson models compared change in utilization of each service in patients with and without MGUS.

RESULTS

During the 2 months around diagnosis/index date, the rates of emergency room, hospital and outpatient visits were higher for patients with MGUS than patients without MGUS. In the year before MGUS diagnosis, the association was still elevated, although attenuated.

CONCLUSION

Understanding the care of MGUS patients is important given that multiple myeloma patients with a pre-existing MGUS diagnosis may have a better prognosis.

Advances in MGUS diagnosis, risk stratification, and management: introducing myeloma-defining genomic events

In the 1960s, Dr Jan Waldenström argued that patients who had monoclonal proteins without any symptoms or evidence of end-organ damage represented a benign monoclonal gammopathy. In 1978, Dr Robert Kyle introduced the concept of “monoclonal gammopathy of undetermined significance” (MGUS) given that, at diagnosis, it was not possible with available methods (ie, serum protein electrophoresis to define the concentration of M-proteins and microscopy to determine the plasma cell percentage in bone marrow aspirates) to determine which patients would ultimately progress to multiple myeloma. The application of low-input whole-genome sequencing (WGS) technology has circumvented previous problems related to volume of clonal plasma cells and contamination by normal plasma cells and allowed for the interrogation of the WGS landscape of MGUS. As discussed in this chapter, the distribution of genetic events reveals striking differences and the existence of 2 biologically and clinically distinct entities of asymptomatic monoclonal gammopathies. Thus, we already have genomic tools to identify “myeloma-defining genomic events,” and consequently, it is reasonable to consider updating our preferred terminologies. When the clinical field is ready to move forward, we should be able to consolidate current terminologies—from current 7 clinical categories: low-risk MGUS, intermediate-risk MGUS, high-risk MGUS, low-risk smoldering myeloma, intermediate-risk smoldering myeloma, high-risk smoldering myeloma, and multiple myeloma—to future 3 genomic-based categories: monoclonal gammopathy, early detection of multiple myeloma (in which myeloma-defining genomic events already have been acquired), and multiple myeloma (patients who are already progressing and clinically defined cases). Ongoing investigations will continue to advance the field.

Identification of Paraproteins via Serum Immunofixation or Serum Immunosubtraction and Immunoturbidimetric Quantitation of Serum Immunoglobulins in the Laboratory Testing for Monoclonal Gammopathies

Context.—

In laboratory testing for monoclonal gammopathies, paraproteins are identified via serum immunofixation or serum immunosubtraction, and immunoturbidimetric quantitation of serum immunoglobulins is often used.

Objective.—

To evaluate methodologic differences between serum immunofixation and serum immunosubtraction, as well as in the quantitation of serum immunoglobulins on different clinical chemical platforms.

Design.—

Three hundred twenty-two unique routine patient samples were blinded and used for comparison between serum immunofixation on Sebia's HYDRASIS 2 and serum immunosubtraction on Sebia's CAPILLARYS 2, as well as between quantitation results of immunoglobulin A, G, and M on Abbott's ARCHITECT c16000PLUS and Roche's Cobas c 502 module. Microsoft Excel 2019 with the add-on Abacus 2.0 and MedCalc were used for statistical analysis and graphic depiction via bubble diagram, Passing-Bablok regressions, and Bland-Altman plots.

Results.—

The median age of patients was 75 years, and samples with paraproteinemia were nearly evenly split between sexes. Paraprotein identification differed remarkably between immunofixation and immunosubtraction. Quantitation of serum immunoglobulins showed higher values on Abbott's ARCHITECT c16000PLUS when compared with Roche's Cobas c 502 module.

Conclusions.—

Identification of paraproteins via serum immunosubtraction is inferior to serum immunofixation, which can have implications on the diagnosis and monitoring of patients with monoclonal gammopathy. If immunoturbidimetric quantitation of immunoglobulins is used for follow-up, the same clinical-chemical platform should be used consistently.

Phase-Specific and Lifetime Costs of Multiple Myeloma Among Older Adults in the US

IMPORTANCE

Health care costs associated with diagnosis and care among older adults with multiple myeloma (MM) are substantial, with cost of care and the factors involved differing across various phases of the disease care continuum, yet little is known about cost of care attributable to MM from a Medicare perspective.

OBJECTIVE

To estimate incremental phase-specific and lifetime costs and cost drivers among older adults with MM enrolled in fee-for-service Medicare.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted using population-based registry data from the 2007-2015 Surveillance, Epidemiology, and End Results database linked with 2006-2016 Medicare administrative claims data. Data analysis included 4533 patients with newly diagnosed MM and 4533 matched noncancer Medicare beneficiaries from a 5% sample of Medicare to assess incremental MM lifetime and phase-specific costs (prediagnosis, initial care, continuing care, and terminal care) and factors associated with phase-specific incremental MM costs. The study was conducted from June 1, 2019, to April 30, 2021.

MAIN OUTCOMES AND MEASURES

Incremental MM costs were calculated for the disease lifetime and the following 4 phases of care: prediagnosis, initial, continuing care, and terminal.

RESULTS

Of the 4533 patients with MM included in the study, 2374 were women (52.4%), 3418 (75.4%) were White, and mean (SD) age was 75.8 (6.8) years (2313 [51.0%] aged ≥75 years). The characteristics of the control group were similar; however, mean (SD) age was 74.2 (8.8) years (2839 [62.6%] aged ≤74 years). Mean adjusted incremental MM lifetime costs were $184 495 (95% CI, $183 099-$185 968). Mean per member per month phase-specific incremental MM costs were estimated to be $1244 (95% CI, $1216-$1272) for the prediagnosis phase, $11 181 (95% CI, $11 052-$11 309) for the initial phase, $5634 (95% CI, $5577-$5694) for the continuing care phase, and $6280 (95% CI, $6248-$6314) for the terminal phase. Although inpatient and outpatient costs were estimated as the major cost drivers for the prediagnosis (inpatient, 55.8%; outpatient, 40.2%), initial care (inpatient, 38.1%; outpatient, 35.5%), and terminal (inpatient, 33.0%; outpatient, 34.6%) care phases, prescription drugs (44.9%) were the largest cost drivers in the continuing care phase.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that there is substantial burden to Medicare associated with diagnosis and care among older adults with MM, and the cost of care and cost drivers vary across different phases of the cancer care continuum. The study findings might aid policy discussions regarding MM care and coverage and help further the development of alternative payment models for MM, accounting for differential costs across various phases of the disease continuum and their drivers.

Iceland screens, treats, or prevents multiple myeloma (iStopMM): a population-based screening study for monoclonal gammopathy of undetermined significance and randomized controlled trial of follow-up strategies

Monoclonal gammopathy of undetermined significance (MGUS) precedes multiple myeloma (MM). Population-based screening for MGUS could identify candidates for early treatment in MM. Here we describe the Iceland Screens, Treats, or Prevents Multiple Myeloma study (iStopMM), the first population-based screening study for MGUS including a randomized trial of follow-up strategies. Icelandic residents born before 1976 were offered participation. Blood samples are collected alongside blood sampling in the Icelandic healthcare system. Participants with MGUS are randomized to three study arms. Arm 1 is not contacted, arm 2 follows current guidelines, and arm 3 follows a more intensive strategy. Participants who progress are offered early treatment. Samples are collected longitudinally from arms 2 and 3 for the study biobank. All participants repeatedly answer questionnaires on various exposures and outcomes including quality of life and psychiatric health. National registries on health are cross-linked to all participants. Of the 148,704 individuals in the target population, 80 759 (54.3%) provided informed consent for participation. With a very high participation rate, the data from the iStopMM study will answer important questions on MGUS, including potentials harms and benefits of screening. The study can lead to a paradigm shift in MM therapy towards screening and early therapy.

Diagnosis and Management of Monoclonal Gammopathy and Smoldering Multiple Myeloma

The presence of monoclonal proteins is common, with a prevalence in the United States around 5% that increases with age. Although most patients are asymptomatic, most cases are caused by a clonal plasma cell disorder. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic precursor conditions with variable risk of progression to multiple myeloma. In recent years, significant progress has been made to better understand the factors that lead to the development of symptoms and progression to myeloma. This review summarizes the current diagnosis treatment guidelines for MGUS and SMM and highlights recent advances that underscore a shifting paradigm in the evaluation and management of plasma cell precursor conditions.

A Single-Center Retrospective Study to Investigate the Follow-Up of Patients with Monoclonal Proteinemia by Community Physicians in the UK

Background

We determined the detection rate of monoclonal gammopathy of undetermined significance (MGUS) and follow-up of MGUS patients in a center that uses reflex testing at globulin levels outside the reference range as part of its routine service to detect monoclonal protein (M-protein). We recorded the natural history and follow-up of these patients. This is one of the first reports on the diagnosis and follow-up of MGUS patients within the UK.

Patients and Methods

A total of 163 patients diagnosed in 2006 and 393 patients with M-protein on long-term follow-up in 2006 were followed over a period of 10 years (y) by community physicians with laboratory support.

Results

In 2006, newly diagnosed patients with an M-protein and total number of patients as a percentage of the Worcestershire population were, respectively, 0.025%, 0.045% (at 45–49y); 0.1%, 0.25% (at 60–64y); and 0.26%, 1.12% (at 75–79y). Patients with M-protein had a survival of 35.5% at 10 y and 43.5% at >10y follow-up. Kaplan–Meier analysis of patients with an M-protein showed that lymphoplasma-cell proliferative disorders (LPD)-free survival was 91% for both 10y and >10y follow-up. LPD-free survival decreased to approximately 73% when competing causes (death due to unrelated causes, transient M-protein, loss to follow-up) were censored. Progression to LPD occurred at initial M-protein values of 3g/L at diagnosis. During follow-up, 38.3% died without evidence of LPD, 12% were diagnosed with transient M-protein, 8.7% developed LPD, 10.9% had stable M-protein, 4.9% showed increasing M-protein, and 25.2% were lost to follow-up. Survival curves showed that M-protein isotype contributed to LPD-free survival in the order IgG=IgM>IgA>biclonal M-protein.

Conclusion

Geographical variations in the diagnosis and follow-up of MGUS patients in the UK need investigation. From public health viewpoint, it is essential to determine MGUS follow-up to improve clinical care and individualise risk-based follow-up of patients.

Dissecting racial disparities in multiple myeloma

Multiple myeloma (MM) is a fatal plasma cell dyscrasia with a median overall survival of 5 to 10 years. MM progresses from the more common but often subclinical precursor states of monoclonal gammopathy of undetermined significance (MGUS), and smoldering multiple myeloma (SMM) to overt MM. There are large racial disparities in all stages of the disease. Compared with Whites, Blacks have an increased MGUS and MM risk and higher mortality rate, and have not experienced the same survival gains over time. The roots of this disparity are likely multifactorial in nature. Comparisons of Black and White MGUS and MM patients suggest that differences in risk factors, biology, and clinical characteristics exist by race or ancestry, which may explain some of the observed disparity in MM. However, poor accrual of Black MGUS and MM patients in clinical and epidemiological studies has limited our understanding of this disparity and hindered its elimination. Disparities in MM survival also exist but appear to stem from inferior treatment utilization and access rather than underlying pathogenesis. Innovative and multidisciplinary approaches are urgently needed to enhance our understanding of disparities that exist at each stage of the MM disease continuum and facilitate their elimination.

The prevalence and significance of monoclonal gammopathy of undetermined significance in acute medical admissions

Monoclonal gammopathy of undetermined significance (MGUS) affects 3·2% of adults aged >50 years. MGUS carries a life-long risk of progression to multiple myeloma and causes complications including infection and renal impairment; common causes of hospital admission. This study aimed to assess MGUS prevalence in emergency medical hospital admissions. Patients were recruited from unselected emergency medical admissions in a hospital in the United Kingdom. Serum protein electrophoresis was performed, with immunofixation of abnormal results. Reason for admission and routine test results were recorded. After education about MGUS and myeloma, patients chose whether they wished to be informed of new diagnoses. A total of 660 patients were tested and 35 had a paraprotein suggestive of MGUS. The overall rate of MGUS was 5·3%. MGUS prevalence in those aged >50 years was 6·94%, higher than the previously published rate of 3·2% (P < 0·0005). There were higher rates in those with chronic kidney disease (13·75% vs. 4·14%, P = 0·002), heart failure (14% vs. 4·59%, P = 0·012), anaemia (8·96% vs. 3·41%, P = 0·003) or leucocytosis (9·33% vs. 3·04%, P = 0·002). In all, 96% of patients wished to be informed of their screening results. The prevalence of MGUS in emergency hospital admissions is higher than expected based on previous population-based rates. This may suggest a selected population for screening.

Impact of prior diagnosis of monoclonal gammopathy on outcomes in newly diagnosed multiple myeloma

Multiple myeloma (MM) is consistently preceded by monoclonal gammopathy of undetermined significance (MGUS), smoldering myeloma (SMM), or solitary plasmacytoma (SPC). There is a lack of data regarding impact of these pre-existing monoclonal gammopathies (MGs) on MM outcomes. Patients with prior diagnosis of MGUS, SMM, or PC from 1973 to 2015 (cases) were identified from our institution's database and compared to those without a known MG (controls). The primary outcome of interest was overall survival (OS). Multivariate analysis was performed to ascertain factors impacting all-cause mortality. We identified 774 patients with a prior diagnosis of MGUS, SMM or SPC (cases) and a control population (1:2) matched for the year of diagnosis (n = 1548). After a median follow-up of 81 months, the cases showed a longer median OS than the controls (71 months vs. 56 months). The improved OS was limited to those with a known prior diagnosis of SMM (80 months) and SPC (95 months), compared to MGUS (60 months). Multivariable analysis revealed that MM patients with known prior MG had less overall mortality than those without, and this was limited to prior SMM/SPC group (HR 0.68, 95% CI: 0.50-0.93), as compared to the MGUS group (HR 0.83, 95% CI: 0.66-1.05).

A longitudinal big data approach for precision health

Precision health relies on the ability to assess disease risk at an individual level, detect early preclinical conditions and initiate preventive strategies. Recent technological advances in omics and wearable monitoring enable deep molecular and physiological profiling and may provide important tools for precision health. We explored the ability of deep longitudinal profiling to make health-related discoveries, identify clinically relevant molecular pathways and affect behavior in a prospective longitudinal cohort (n = 109) enriched for risk of type 2 diabetes mellitus. The cohort underwent integrative personalized omics profiling from samples collected quarterly for up to 8 years (median, 2.8 years) using clinical measures and emerging technologies including genome, immunome, transcriptome, proteome, metabolome, microbiome and wearable monitoring. We discovered more than 67 clinically actionable health discoveries and identified multiple molecular pathways associated with metabolic, cardiovascular and oncologic pathophysiology. We developed prediction models for insulin resistance by using omics measurements, illustrating their potential to replace burdensome tests. Finally, study participation led the majority of participants to implement diet and exercise changes. Altogether, we conclude that deep longitudinal profiling can lead to actionable health discoveries and provide relevant information for precision health.

Immune marker changes and risk of multiple myeloma: a nested case-control study using repeated pre-diagnostic blood samples

Biomarkers reliably predicting progression to multiple myeloma (MM) are lacking. Myeloma risk has been associated with low blood levels of monocyte chemotactic protein-3 (MCP-3), macrophage inflammatory protein-1 alpha (MIP-1α), vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), fractalkine, and transforming growth factor-alpha (TGF-α). In this study, we aimed to replicate these findings and study the individual dynamics of each marker in a prospective longitudinal cohort, thereby examining their potential as markers of myeloma progression. For this purpose, we identified 65 myeloma cases and 65 matched cancer-free controls each with two donated blood samples within the Northern Sweden Health and Disease Study. The first and repeated samples from myeloma cases were donated at a median 13 and 4 years, respectively, before the myeloma was diagnosed. Known risk factors for progression were determined by protein-, and immunofixation electrophoresis, and free light chain assays. We observed lower levels of MCP-3, VEGF, FGF-2, and TGF-α in myeloma patients than in controls, consistent with previous data. We also observed that these markers decreased among future myeloma patients while remaining stable in controls. Decreasing trajectories were noted for TGF-α (P=2.5 × 10⁻⁴) indicating progression to MM. Investigating this, we found that low levels of TGF-α assessed at the time of the repeated sample were independently associated with risk of progression in a multivariable model (hazard ratio = 3.5; P=0.003). TGF-α can potentially improve early detection of MM.

Computational Model of Progression to Multiple Myeloma Identifies Optimum Screening Strategies

PURPOSE

Recent advances have uncovered therapeutic interventions that might reduce the risk of progression of premalignant diagnoses, such as monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM). It remains unclear how to best screen populations at risk and how to evaluate the ability of these interventions to reduce disease prevalence and mortality at the population level. To address these questions, we developed a computational modeling framework.

MATERIALS AND METHODS

We used individual-based computational modeling of MGUS incidence and progression across a population of diverse individuals to determine best screening strategies in terms of screening start, intervals, and risk-group specificity. Inputs were life tables, MGUS incidence, and baseline MM survival. We measured MM-specific mortality and MM prevalence after MGUS detection from simulations and mathematic modeling predictions.

RESULTS

Our framework is applicable to a wide spectrum of screening and intervention scenarios, including variation of the baseline MGUS to MM progression rate and evolving MGUS, in which progression increases over time. Given the currently available point estimate of progression risk reduction to 61% risk, starting screening at age 55 years and performing follow-up screening every 6 years reduced total MM prevalence by 19%. The same reduction could be achieved with starting screening at age 65 years and performing follow-up screening every 2 years. A 40% progression risk reduction per patient with MGUS per year would reduce MM-specific mortality by 40%. Specifically, screening onset age and screening frequency can change disease prevalence, and progression risk reduction changes both prevalence and disease-specific mortality. Screening would generally be favorable in high-risk individuals.

CONCLUSION

Screening efforts should focus on specifically identified groups with high lifetime risk of MGUS, for which screening benefits can be significant. Screening low-risk individuals with MGUS would require improved preventions.

What is the significance of monoclonal gammopathy of undetermined significance?

Monoclonal gammopathy of undetermined significance (MGUS) is characterised by the presence of a monoclonal paraprotein in the blood, without the characteristic end organ damage seen in multiple myeloma. MGUS is more common in older age groups and has a risk of progression to myeloma of 1% per year. Population screening is not currently recommended, but retrospective studies have suggested improvements in myeloma outcomes in those under MGUS follow-up; in addition, MGUS has associated complications, including fracture, osteoporosis, renal disease and infection, which can be treated. Given this increasing evidence of disease related directly to MGUS, strategies for early identification might be needed. In this review, we discuss the complications of MGUS and whether MGUS fulfils the criteria needed to implement a screening programme. We also highlight areas where more evidence is needed, including identification of a higher risk population to make screening more practical and economically viable.

Risk of MGUS in relatives of multiple myeloma cases by clinical and tumor characteristics

We and others have shown increased risk of monoclonal gammopathy of undetermined significance (MGUS) in first-degree relatives of patients with multiple myeloma (MM). Whether familial risk of MGUS differs by the MM proband's age at onset, tumor or clinical characteristics is unknown. MM and smoldering MM (SMM) cases (N = 430) were recruited from the Mayo Clinic in Rochester, Minnesota between 2005-2015. First-degree relatives over age 40 provided serum samples for evaluation of MGUS (N = 1179). Age and sex specific rates of MGUS among first-degree relatives were compared to a population-based sample. Cytogenetic subtypes were classified by Fluorescence in situ hybridization. MGUS was detected in 75 first-degree relatives for an age- and sex- adjusted prevalence of 5.8% (95% CI: 4.5-7.2). Prevalence of MGUS in first-degree relatives was 2.4 fold (95% CI: 1.9-2.9) greater than expected rates. Familial risk did not differ by proband's age at diagnosis, gender, isotype, IgH translocation, or trisomy. This study confirms first-degree relatives of MM cases have a significantly higher risk of MGUS compared to the general population, regardless of age, gender, or tumor characteristics. In selected situations, such as multiple affected first-degree relatives, screening of first-degree relatives of MM cases could be considered for follow-up and prevention strategies.

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.

Shall we treat smoldering multiple myeloma in the near future?

In recent years, several new drugs have been approved for the treatment of multiple myeloma. Many of these newer drugs are highly efficacious and less toxic than older chemotherapy drugs. In 2014, the diagnostic criteria for multiple myeloma were revised. The intent with the new criteria was to identify patients who require therapy at an earlier stage than at manifestation of organ complications. A subset of patients who were previously defined as having high-risk smoldering multiple myeloma was redefined as having multiple myeloma. In this context, it is logical to raise questions regarding the optimal clinical management of patients who are diagnosed with smoldering multiple myeloma in the current era. When is the optimal time to start therapy? Do the clinical trajectories for patients suggest there are distinct sub-entities hidden in the current category of smoldering multiple myeloma? How can we move the field forward from here? This paper reviews and dissects data and models on the topics of clinical features, underlying biology, and early treatment trials in smoldering multiple myeloma. The text highlights assumptions, facts, and gaps in the literature. As indicated in the title of the paper, the recurrent theme of the text is this: shall we treat smoldering multiple myeloma in the near future?

Exploring Big Data in Hematological Malignancies: Challenges and Opportunities

Secondary analysis of large datasets has become a useful alternative to address research questions outside the reach of clinical trials. It is increasingly utilized in hematology and oncology. In this review, we provided an overview of some examples of commonly used large datasets in the USA and described common research themes that can be pursued using such a methodology. We selected a sample of 14 articles on adult hematologic malignancies published in 2015 and highlighted their contributions as well as limitations.

Monoclonal Gammopathy of Undetermined Significance: Follow-up Patterns in the United States and Concordance With Clinical Practice Guidelines

Objective

To determine follow-up practice patterns of US patients with monoclonal gammopathy of undetermined significance (MGUS) and their concordance with 4 clinical practice guidelines.

Patients and Methods

In a retrospective analysis of adult patients using the OptumLabs Data Warehouse database, we identified those who had an incident diagnosis of MGUS from January 1, 2006, through December 31, 2013, no history or subsequent diagnosis of lymphoplasmacytic malignancy, and at least 2 years of follow-up.

Results

A total of 11,676 patients with MGUS were included in the study. During the first 2 years after MGUS diagnosis, the distribution of patients by mean interval between visits was as follows: less than 6 months, 12.7%; every 6 to 12 months, 25.2%; every 13 to 24 months, 17.7%; and longer than 24 months, 44.4%. A higher proportion of patients were followed up at intervals of less than 13 months over time, from 32.7% to 41.1% (P<.001). Patients 60 years or older were more likely to be followed up at intervals of less than 13 months; those from the Northeast or younger than 50 years were more likely to be followed up at intervals longer than 24 months compared with their counterparts (P<.001). More than half of the patients 80 years or older were followed up at intervals of less than 6 months (12.3%), 6 to 12 months (27.8%), or 13 to 24 months (18.2%). Only approximately half of the patients (41.1%-58.8%) with MGUS diagnosed in 2013 were concordant with any of the 4 clinical guidelines.

Conclusion

The MGUS follow-up practice patterns varied geographically and demographically and were frequently discordant with guideline recommendations. A large proportion of patients with limited life expectancy had frequent follow-up visits.

Towards Stratified Medicine in Plasma Cell Myeloma

Plasma cell myeloma is a clinically heterogeneous malignancy accounting for approximately one to 2% of newly diagnosed cases of cancer worldwide. Treatment options, in addition to long-established cytotoxic drugs, include autologous stem cell transplant, immune modulators, proteasome inhibitors and monoclonal antibodies, plus further targeted therapies currently in clinical trials. Whilst treatment decisions are mostly based on a patient’s age, fitness, including the presence of co-morbidities, and tumour burden, significant scope exists for better risk stratification, sub-classification of disease, and predictors of response to specific therapies. Clinical staging, recurring acquired cytogenetic aberrations, and serum biomarkers such as β-2 microglobulin, and free light chains are in widespread use but often fail to predict the disease progression or inform treatment decision making. Recent scientific advances have provided considerable insight into the biology of myeloma. For example, gene expression profiling is already making a contribution to enhanced understanding of the biology of the disease whilst Next Generation Sequencing has revealed great genomic complexity and heterogeneity. Pathways involved in the oncogenesis, proliferation of the tumour and its resistance to apoptosis are being unravelled. Furthermore, knowledge of the tumour cell surface and its interactions with bystander cells and the bone marrow stroma enhance this understanding and provide novel targets for cell and antibody-based therapies. This review will discuss the development in understanding of the biology of the tumour cell and its environment in the bone marrow, the implementation of new therapeutic options contributing to significantly improved outcomes, and the progression towards more personalised medicine in this disorder.

Genomewide profiling of copy-number alteration in monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a benign condition with an approximate 1% annual risk of symptomatic plasma cell disorder development, mostly to multiple myeloma (MM). We performed genomewide screening of copy-number alterations (CNAs) in 90 MGUS and 33 MM patients using high-density DNA microarrays. We identified CNAs in a smaller proportion of MGUS (65.6%) than in MM (100.0%, P = 1.31 × 10^-5 ) and showed median number of CNAs is lower in MGUS (3, range 0-22) than in MM (13, range 4-38, P = 1.82 × 10^-10 ). In the MGUS cohort, the most frequent losses were located at 1p (5.6%), 6q (6.7%), 13q (30.0%), 14q (14.4%), 16q (8.9%), 21q (5.6%), and gains at 1q (23.3%), 2p (6.7%), 6p (13.3%), and Xq (7.8%). Hyperdiploidy was detected in 38.9% of MGUS cases, and the most frequent whole chromosome gains were 3 (25.6%), 5 (23.3%), 9 (37.8%), 15 (23.3%), and 19 (32.2%). We also identified CNAs such as 1p, 6q, 8p, 12p, 13q, 16q losses, 1q gain and hypodiploidy, which are potentially associated with an adverse prognosis in MGUS. In summary, we showed that MGUS is similar to MM in that it is a genetically heterogeneous disorder, but overall cytogenetic instability is lower than in MM, which confirms that genetic abnormalities play important role in monoclonal gammopathies.