18F-FDG PET/CT is useful for determining survival outcomes of patients with multiple myeloma classified as stage II and III with the Revised International Staging System

Evidence-based Korean guidelines for the clinical management of multiple myeloma: addressing 12 key clinical questions

Multiple myeloma (MM), a hematological malignancy, is characterized by malignant plasma cell proliferation in the bone marrow. Recent treatment advances have significantly improved patient outcomes associated with MM. In this study, we aimed to develop comprehensive, evidence-based guidelines for the diagnosis, prognosis, and treatment of MM. We identified 12 key clinical questions essential for MM management, guiding the extensive literature review and meta-analysis of the study. Our guidelines provide evidence-based recommendations by integrating patient preferences with survey data. These recommendations include current and emerging diagnostic tools, therapeutic agents, and treatment strategies. By prioritizing a patient-centered approach and rigorous data analysis, these guidelines were developed to enhance MM management, both in Korea and globally.

Construction and validation of an 18F-FDG-PET/CT-based prognostic model to predict progression-free survival in newly diagnosed multiple myeloma patients

OBJECTIVE

To investigate the relationship between 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) related parameters and the prognosis of multiple myeloma and to establish and validate a prediction model regarding the progression-free survival (PFS) of multiple myeloma.

METHODS

A retrospective analysis of 126 newly diagnosed multiple myeloma patients who attended Nanjing Drum Tower Hospital from 2014-2021. All patients underwent PET/CT before treatment and were divided into a training cohort (n = 75) and a validation cohort (n = 51). Multivariate Cox proportional hazard regression analysis incorporated PET/CT-related parameters and clinical indicators. A nomogram was established to individually predict PFS in MM patients. The model was evaluated by calculating the C-index and calibration curve.

RESULTS

Here, 4.2 was used as the cut-off value of SUVmax to divide patients into high and low groups. PFS significantly differed between patients in the high-SUVmax group and low-SUVmax group, and SUVmax was an independent predictor of PFS in newly diagnosed multiple myeloma (NDMM) patients. Univariate and multivariate cox regression analysis suggested that lactate dehydrogenase (LDH), bone marrow plasma cell (BMPC), and SUVmax affected PFS. These factors were incorporated to construct a nomogram model for predicting PFS at 1 and 2 years in NDMM patients. The C-index and calibration curves of the nomogram exhibited good accuracy and consistency, and the DCA curves suggested that the model had good clinical utility.

CONCLUSION

The PET/CT parameter SUVmax is closely related to the prognosis of myeloma patients. The nomogram constructed in this study based on PET/CT-related parameters and clinical indicators individually predicts the PFS rate of NDMM patients and enables further risk stratification of NDMM patients.

Coefficient of variation and texture analysis of 18F-FDG PET/CT images for the prediction of outcome in patients with multiple myeloma

In multiple myeloma (MM) bone marrow infiltration by monoclonal plasma cells can occur in both focal and diffuse manner, making staging and prognosis rather difficult. The aim of our study was to test whether texture analysis of 18 F-2-deoxy-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) images can predict survival in MM patients. Forty-six patients underwent 18 F-FDG-PET/CT before treatment. We used an automated contouring program for segmenting the hottest focal lesion (FL) and a lumbar vertebra for assessing diffuse bone marrow involvement (DI). Maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean) and texture features such as Coefficient of variation (CoV), were obtained from 46 FL and 46 DI. After a mean follow-up of 51 months, 24 patients died of myeloma and were compared to the 22 survivors. At univariate analysis, FL SUVmax (p = 0.0453), FL SUVmean (p = 0.0463), FL CoV (p = 0.0211) and DI SUVmax (p = 0.0538) predicted overall survival (OS). At multivariate analysis only FL CoV and DI SUVmax were retained in the model (p = 0.0154). By Kaplan-Meier method and log-rank testing, patients with FL CoV below the cut-off had significantly better OS than those with FL CoV above the cut-off (p = 0.0003), as well as patients with DI SUVmax below the threshold versus those with DI SUVmax above the threshold (p = 0.0006). Combining FL CoV and DI SUVmax by using their respective cut-off values, a statistically significant difference was found between the resulting four survival curves (p = 0.0001). Indeed, patients with both FL CoV and DI SUVmax below their respective cut-off values showed the best prognosis. Conventional and texture parameters derived from 18F-FDG PET/CT analysis can predict survival in MM patients by assessing the heterogeneity and aggressiveness of both focal and diffuse infiltration.

[68Ga]Pentixafor PET/CT for staging and prognostic assessment of newly diagnosed multiple myeloma: comparison to [18F]FDG PET/CT

PURPOSE

To evaluate the prognostic performance of [68Ga]Pentixafor PET/CT at baseline for staging of patients with newly diagnosed multiple myeloma (MM) and to compare it with [18F]FDG PET/CT and the Revised-International Staging System (R-ISS).

METHODS

Patients who underwent [68Ga]Pentixafor and [18F]FDG PET/CT imaging were retrospectively included. Patient staging was performed according to the Durie-Salmon PLUS staging system based on [68Ga]Pentixafor PET/CT and [18F]FDG PET/CT images, and the R-ISS. Progression-free survival (PFS) at patient follow-up was estimated using the Kaplan-Meier estimator and compared using the log-rank test. Area under the receiver operating characteristic curve (AUC) was calculated to assess predictive performance.

RESULTS

Fifty-five MM patients were evaluated. Compared with [18F]FDG PET, [68Ga]Pentixafor PET detected 25 patients as the same stage, while 26 patients were upstaged and 4 patients were downstaged (P = 0.001). After considering the low-dose CT data, there was no statistically significant difference in the number of patients classified in each stage using [68Ga]Pentixafor PET/CT and [18F]FDG PET/CT (P = 0.091). [68Ga]Pentixafor PET/CT-based staging discriminated PFS outcomes in patients with different disease stages (stage I vs. stage II, stage I vs. stage III, and stage II vs. stage III; all P < 0.05), whereas for [18F]FDG PET/CT, there was only a difference in median PFS between stage I and III (P = 0.021). When staged by R-ISS, the median PFS for stage III was significantly lower than that for stage I and II (P = 0.008 and 0.035, respectively). When predicting 2-year PFS based on staging, the AUC of [68Ga]Pentixafor PET/CT was significantly higher than that of [68Ga]Pentixafor PET (0.923 vs. 0.821, P = 0.002), [18F]FDG PET (0.923 vs. 0.752 P = 0.002), and R-ISS (0.923 vs. 0.776, P = 0.005).

CONCLUSIONS

[68Ga]Pentixafor PET/CT-based staging possesses substantial potential to predict disease progression in newly diagnosed MM patients.

Positron Emission Tomography/Computed Tomography Transformation of Oncology: Multiple Myeloma

This article provides a comprehensive review of the role of 2-deoxy-2-[18F]fluoro-d-glucose (18F FDG) positron emission tomography/computed tomography (PET/CT) in multiple myeloma (MM) and related plasma cell disorders. MM is a hematologic malignancy characterized by the neoplastic proliferation of plasma cells. 18F FDG PET/CT integrates metabolic and anatomic information, allowing for accurate localization of metabolically active disease. The article discusses the use of 18F FDG PET/CT in initial diagnosis, staging, prognostication, and assessing treatment response. Additionally, it provides valuable insights into the novel imaging targets including chemokine receptor C-X-C motif 4 and CD38.

Hybrid simultaneous whole-body 2-[18F]FDG-PET/MRI imaging in newly diagnosed multiple myeloma: first diagnostic performance and clinical added value results

OBJECTIVES

Mixing diagnostic and prognostic data provided by whole-body MRI (WB-MRI) and 2-18F-fluorodeoxyglucose (2-[18F]FDG) positron emission tomography (2-[18F]FDG-PET) from a single simultaneous imaging technique for newly diagnosed multiple myeloma (NDMM) initial workup seems attractive. However, to date, the published data are scarce and this possibility has not been fully explored. In this prospective study, we aimed to explore the diagnostic performance and added clinical value of WB-2-[18F]FDG-PET/MRI imaging in NDMM.

METHODS

All patients with confirmed NDMM at the Nantes University Hospital were prospectively enrolled in this study and underwent WB-2-[18F]FDG-PET/MRI imaging on a 3-T Biograph mMR before receiving treatment. Before imaging, they were considered either as symptomatic or as smoldering MM (SMM). Diagnostic performance of global WB-2-[18F]FDG-PET/MRI imaging, as well as PET and MRI separately for FL and diffuse BMI detection, was assessed and compared in each group. PET-based (maximal standardized uptake value, SUVmax) and MRI-based (mean apparent diffusion coefficient value, ADCmean) quantitative features were collected for FL/para-medullary disease (PMD)/bone marrow and were compared.

RESULTS

A total of 52 patients were included in this study. PET and MRI were equally effective at detecting patients with FL (69% vs. 75%) and with diffuse BMI (62% for both) in the symptomatic MM group. WB-2-[18F]FDG-PET/MRI imaging detected FL in 22% of patients with SMM (with a higher diagnostic performance for MRI), resulting in a significant impact on clinical management in this population. SUVmax and ADCmean quantitative features were weakly or not correlated.

CONCLUSIONS

WB-2-[18F]FDG-PET/MRI could represent the next-generation imaging modality for MM.

KEY POINTS

• Whole-body 2-[18F]FDG-PET/MRI imaging detected at least one focal bone lesion in 75% of patients with symptomatic multiple myeloma, and PET and MRI were equally effective at identifying patients with a focal bone lesion. • Whole-body 2-[18F]FDG-PET/MRI imaging detected a focal bone lesion in 22% of patients with smoldering multiple myeloma (with a higher diagnostic performance for MRI). • MRI had a significant impact on clinical management of smoldering multiple myeloma.

Head-to-Head Comparison of FDG and Radiolabeled FAPI PET: A Systematic Review of the Literature

FAPI-based radiopharmaceuticals are a novel class of tracers, mainly used for PET imaging, which have demonstrated several advantages over [18F]FDG, especially in the case of low-grade or well-differentiated tumors. We conducted this systematic review to evaluate all the studies where a head-to-head comparison had been performed to explore the potential utility of FAPI tracers in clinical practice. FAPI-based radiopharmaceuticals have shown promising results globally, in particular in detecting peritoneal carcinomatosis, but studies with wider populations are needed to better understand all the advantages of these new radiopharmaceuticals.

Comprehensive analysis of ferroptosis-related genes in immune infiltration and prognosis in multiple myeloma

Background: One particular type of cellular death that is known as ferroptosis is caused by the excessive lipid peroxidation. It is a regulated form of cell death that can affect the response of the tumor cells. Currently, it is not known if the presence of this condition can affect the prognosis of patients with multiple myeloma (MM). Methods: In this study, we studied the expression differences and prognostic value of ferroptosis-related genes (FRGs) in MM, and established a ferroptosis risk scoring model. In order to improve the prediction accuracy and clinical applicability, a nomogram was also established. Through gene enrichment analysis, pathways closely related to high-risk groups were identified. We then explored the differences in risk stratification in drug sensitivity and immune patterns, and evaluated their value in prognostic prediction and treatment response. Lastly, we gathered MM cell lines and samples from patients to confirm the expression of marker FRGs using quantitative real-time PCR (qRT-PCR). Results: The ability to predict the survival of MM patients is a challenging issue. Through the use of a risk model derived from ferroptosis, we were able to develop a more accurate prediction of the disease's prognosis. They were then validated by a statistical analysis, which showed that the model is an independent factor in the prognosis of MM. Patients of high ferroptosis risk scores had a much worse chance of survival than those in the low-risk groups. The calibration and power of the nomogram were also strong. We noted that the link between the ferroptosis risk score and the clinical treatment was suggested by the FRG's significant correlation with the immune checkpoint genes and the medication sensitivity. We validated the predictive model using qRT-PCR. Conclusion: We demonstrated the association between FRGs and MM, and developed a new risk model for prognosis in MM patients. Our study sheds light on the potential clinical relevance of ferroptosis in MM and highlights its potential as a therapeutic target for patients with this disease.

Cluster analysis of autoencoder-extracted FDG PET/CT features identifies multiple myeloma patients with poor prognosis

F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is a robust imaging modality used for staging multiple myeloma (MM) and assessing treatment responses. Herein, we extracted features from the FDG PET/CT images of MM patients using an artificial intelligence autoencoder algorithm that constructs a compressed representation of input data. We then evaluated the prognostic value of the image-feature clusters thus extracted. Conventional image parameters including metabolic tumor volume (MTV) were measured on volumes-of-interests (VOIs) covering only the bones. Features were extracted with the autoencoder algorithm on bone-covering VOIs. Supervised and unsupervised clustering were performed on image features. Survival analyses for progression-free survival (PFS) were performed for conventional parameters and clusters. In result, supervised and unsupervised clustering of the image features grouped the subjects into three clusters (A, B, and C). In multivariable Cox regression analysis, unsupervised cluster C, supervised cluster C, and high MTV were significant independent predictors of worse PFS. Supervised and unsupervised cluster analyses of image features extracted from FDG PET/CT scans of MM patients by an autoencoder allowed significant and independent prediction of worse PFS. Therefore, artificial intelligence algorithm-based cluster analyses of FDG PET/CT images could be useful for MM risk stratification.

Clinical Value of FDG-PET/CT in Multiple Myeloma: An Update

FDG-PET/CT is a standardized imaging technique that has reached a great importance in the management of patients affected by Multiple Myeloma. It is proved, in fact, that it allows a deep evaluation of therapy efficacy and provides several prognostic indexes both at staging and after therapy. For this reason, it is now recognised as a gold standard for therapy assessment. Beside this, in reacent years FDG-PET/CT contribution to the understanding of Multiple Myeloma has progressively grown. Papers have been published analyzing the prognostic value of active disease volume measurement and standardization issues, the meaning of FDG positive paramedullary and extrameduallary disease, the prognostic impact of FDG positive minimal residual disease, the relation between focal lesions and clonal eterogenity of this disease and the comparison with whole body DWI-MR in terms of detection and therapy assessment. These newer aspects not of clinical impact yet, of FDG-PET/CT in Multiple Myeloma will be presented and discussed in this review.

Prognostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography at diagnosis in untreated multiple myeloma patients: a systematic review and meta-analysis

Multiple myeloma is a clonal B-lymphocyte tumor of terminally differentiated plasma cells. ¹⁸F-FDG PET/CT can provide valuable data for the diagnosis, restaging, and evaluate prognosis of multiple myeloma (MM). This meta-analysis aimed to evaluate the prognostic value of pre-treatment ¹⁸F-FDG PET/CT at diagnosis in MM patients. Related researches came from Embase, PubMed, and Cochrane Library databases through a systematic search, and the last one was updated on April 26, 2021. Cochran Q test and I-squared statistics were used to test for heterogeneity among the studies analyzed. The fixed model and random model were used to combine results when appropriate. Stata 12.0 was used to perform statistical analysis, and p < 0.05 was considered statistically significant. A total of 16 articles with 2589 patients were included in this study. Our results indicated PET/CT has an excellent prognostic role in MM, that higher SUV_max, more FL and EMD were associated with poor OS and PFS. SUVmax: OS (HR 1.89, 95% CI 1.47-2.44), PFS (HR 1.34, 95% CI 1.18-1.51); Fl: OS (HR 2.65, 95% CI 1.83-3.79), PFS (HR 1.61, 95% CI 1.40-1.86); EMD: OS (HR 2.11, 95% CI 1.41-3.16), PFS (HR 2.18, 95% CI 1.69-2.81). Furthermore, similar results were observed in most subgroup analyzes. Conclusion Pre-treatment ¹⁸F-FDG PET/CT examination has prognostic value for myeloma patients and has guiding significance for clinical treatment.

Prognostic value of semi-quantitative parameters of 18F-FDG PET/CT in newly diagnosed multiple myeloma patients

OBJECTIVE

To investigate the prognostic value of fluroine-18 fluorodexyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) semi-quantitative parameter in newly diagnosed multiple myeloma (NDMM) and to design a new staging system including ¹⁸F-FDG PET/CT semi-quantitative parameters for NDMM.

METHODS

A total of 38 NDMM patients who underwent ¹⁸F-FDG PET/CT examination in Yichang Central People's Hospital from February 2014 to April 2021 were collected. The relationship between the characteristics of ¹⁸F-FDG PET/CT (metabolic tumor volume of all lesions (aMTV), total lesion glycolysis of all lesions (aTLG), maximum standardized uptake values (SUVmax) of the lesion with largest MTV (mSUVmax), extramedullary disease (EMD), focal lesions (FLs)), the laboratory parameters, and prognostic parameters (progression-free survival (PFS) and overall survival (OS)) were analyzed retrospectively. SPSS 25.0 statistical software was used for statistical processing, Kaplan-Meier method was used for survival analysis, Log-rank method was used for univariate analysis, and Cox proportional risk model was used for multivariate analysis.

RESULTS

Univariate analysis showed that aMTV ≥ 90.97cm³, aTLG ≥ 283.31 g, hemoglobin (Hb) < 100 g/L, focal lesions (FLs) ≥ 10, (percentage of circulating plasma cells (CPC%) ≥ 30%, creatinine (Cr) ≥ 177umol/L, lactic dehydrogenase (LDH) ≥ 250 g/L might be the adverse prognostic factors of PFS in patients with NDMM, all p < 0.05; aMTV ≥ 90.97 cm³, aTLG ≥ 283.31 g, Hb < 100 g/L, FLs ≥ 10, mSUVmax ≥ 5.8, the presence of extramedullary disease (EMD) and PCPs ≥ 30% may be adverse prognostic factors for OS in patients with NDMM, all p < 0.05. Multivariate regression analysis showed that aMTV ≥ 90.97 cm³ was an independent risk factor for PFS in NDMM patients, p < 0.05; aMTV ≥ 90.97 cm³, mSUVmax ≥ 5.8, and the presence of EMD were independent risk factors for OS in the NDMM patients, all p < 0.05. According to the multivariate analysis results of OS, the New stage (NS) was performed. The 3-year OS rates of stage I, stage II, and stage III in NDMM patients were 100.0, 53.5, and 32.1%, respectively, p = 0.000.

CONCLUSION

aMTV can predict PFS and OS of NDMM patients better than other parameters. NS which combined with aMTV can predict OS of NDMM patients better and can provide an accurate and simple method for risk stratification of NDMM patients.

Relation of whole-body metabolic tumor volume and total lesion glycolysis on fluorodeoxyglucose PET/computed tomography with clinical and laboratory parameters in newly diagnosed multiple myeloma

OBJECTIVE

This study aims to evaluate the relationships of metabolic fluorodeoxyglucose PET/computed tomography (FDG PET/CT) parameters such as whole-body metabolic tumor volume (WB MTV), WB-total lesion glycolysis (TLG), and bone marrow (BM)-mean standard uptake value (SUVmean) with clinical stage and other prognostic biomarkers in newly diagnosed multiple myeloma (MM) patients.

METHODS

Patients who underwent pretreatment PET/CT with the diagnosis of MM were evaluated retrospectively. The number of focal lesions, WB MTV, WB TLG, and BM SUVmean values were measured on FDG PET/CT images. Clinical stages and prognostic laboratory parameters were recorded the pretreatment period.

RESULTS

WB MTV and WB TLG values were significantly higher in patients with more than three focal lesions on FDG PET/CT scan (all P < 0.001). According to the Revised International Staging System (R-ISS), all WB MTV, WB TLG, and BM SUVmean values are significantly higher in patients with stage 3 disease than in stages 1-2 ( P = 0.027, P = 0.019, P = 0.001, respectively). Serum creatinine level is positively correlated with WB MTV, WB TLG, and BM SUVmean values ( P = 0.020, P = 0.004, P < 0.001, respectively). In addition, the β2 microglobulin level, an essential biochemical prognostic parameter, was positively correlated with the BM SUVmean value ( P = 0.013).

CONCLUSION

The BM SUVmean, WB MTV, and WB TLG values, which reflect FDG avid WB tumor burden, are associated with prognostic biomarkers and R-ISS stage in newly diagnosed MM patients. It contributes to the identification of high-risk patients at the pretreatment staging.

Spinal MRI-Based Radiomics Analysis to Predict Treatment Response in Multiple Myeloma

OBJECTIVE

The aim of this study was to explore the clinical utility of spinal magnetic resonance imaging-based radiomics to predict treatment response (TR) in patients with multiple myeloma (MM).

METHODS

A total of 123 MM patients (85 in the training cohort and 38 in the test cohort) with complete response (CR) (n = 40) or non-CR (n = 83) were retrospectively enrolled in the study. Key feature selection and data dimension reduction were performed using the least absolute shrinkage and selection operator regression. A nomogram was built by combining radiomic signatures and independent clinical risk factors. The prediction performance of the nomogram was assessed using the area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis. Treatment response was assessed by determining the serum and urinary levels of M-proteins, serum-free light chain ratio, and the percentage of bone marrow plasma cells.

RESULTS

Thirteen features were selected to build a radiomic signature. The International Staging System (ISS) stage was selected as an independent clinical factor. The radiomic signature and nomogram showed better calibration and higher discriminatory capacity (AUC of 0.929 and 0.917 for the radiomics and nomogram in the training cohort, respectively, and 0.862 and 0.874 for the radiomics and nomogram in the test cohort, respectively) than the clinical model (AUC of 0.661 and 0.674 in the training and test cohort, respectively). Decision curve analysis confirmed the clinical utility of the radiomics model.

CONCLUSIONS

Nomograms incorporating a magnetic resonance imaging-based radiomic signature and ISS stage help predict the response to chemotherapy for MM and can be useful in clinical decision-making.

18F-FDG-PET/CT in relapsed multiple myeloma: Are prognostic thresholds different from first-line therapy?

Purpose

While ¹⁸F-FDG PET/CT yields valuable prognostic information for patients in first-line therapy of multiple myeloma (MM), its prognostic relevance in relapse is not established. Available studies of relapsed MM describe prognostic thresholds for frequently used PET/CT parameters that are significantly higher than those identified in the first-line setting. The purpose of this study was to evaluate the prognostic role of PET/CT in relapsed MM, based on parameters used in the first-line setting.

Methods

Our retrospective study included 36 patients with MM who had received autologous or allogeneic stem cell transplantation, suffered at least one relapse, and underwent FDG-PET/CT at relapse. Number of focal bone lesions (FL), maximal standardised uptake value (SUVmax), and presence of PET-positive extramedullary lesions (EMD) were analysed.

Results

For the number of FLs, the prognostic value was demonstrated with a cut-off of > 3 (median OS 3.8 months vs. not reached, p = 0.003). Median OS of patients with SUVmax ≤ 4 was not reached, while it was 3.9 months in patients with SUVmax > 4 (p = 0.014). Presence of EMD was a significant prognostic parameter too, with median OS of 3.6 months versus not reached (p = 0.004). The above-mentioned parameters showed prognostic significance for PFS as well. Combination of higher ISS stage and PET/CT parameters identified patients with particularly short OS (3.7 months vs. not reached, p < 0.001) and PFS (3.6 vs. 11.7 months p < 0.001).

Conclusion

The PET/CT parameters SUVmax > 4, nFL > 3, and presence of EMD identify patients with poor prognosis not only in the first-line setting but also in relapsed MM.

18 F-FDG PET/CT and MRI in the Management of Multiple Myeloma: A Comparative Review

During the last two decades, the imaging landscape of multiple myeloma (MM) has evolved with whole-body imaging techniques such as fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) and MRI replacing X-ray skeletal survey. Both imaging modalities have high diagnostic performance at the initial diagnosis of MM and are key players in the identification of patients needing treatment. Diffusion-weighted MRI has a high sensitivity for bone involvement, while 18F-FDG PET/CT baseline parameters carry a strong prognostic value. The advent of more efficient therapeutics, such as immunomodulatory drugs and proteasome inhibitors, has called for the use of sensitive imaging techniques for monitoring response to treatment. Diffusion-weighted MRI could improve the specificity of MRI for tumor response evaluation, but questions remain regarding its role as a prognostic factor. Performed at key time points of treatment in newly diagnosed MM patients, 18F-FDG PET/CT showed a strong association with relapse risk and survival. The deployment of minimal residual disease detection at the cellular or the molecular level may raise questions on the role of these imaging techniques, which will be addressed. This review summarizes and outlines the specificities and respective roles of MRI and 18F-FDG PET/CT in the management of MM.

Comparison of [68Ga]-FAPI PET/CT and [18F]-FDG PET/CT in Multiple Myeloma: Clinical Experience

Objective: In this study, we aimed to compare [68Ga]FAPI PET/CT and [18F]FDG PET/CT imaging to detect lesions in multiple myeloma. Methods: A total of 14 patients with multiple myeloma who underwent [68Ga]FAPI PET/CT and [18F]FDG PET/CT imaging were included in this retrospective study. SUVmax values of [68Ga]FAPI and [18F]FDG were compared according to lesion locations. Also, lesion localization ability of both imaging methods was compared on the patient basis. Results: In 4 of 14 patients, [68Ga]FAPI PET/CT and [18F]FDG PET/CT have not detected any bone lesions. In 8 of the remaining 10 patients [18F]FDG PET/CT detected bone lesions but in this group, 6 patients showed more higher SUVmax values than [18F]FDG PET/CT in [68Ga]FAPI PET/CT.In contrast, 2 of 8 patients showed more higher SUVmax values than [68Ga]FAPI PET/CT in [18F]FDG PET/CT. Moreover, [68Ga]FAPI PET/CT detected bone lesions in two patients, which werenot detected by [18F]FDG PET/CT. Also, in five patients, [68Ga]FAPI PET/CT showed more bone lesions in comparison with[18F]FDG PET/CT. Only one patient, [18F]FDG PET/CT showed more bone lesions. Three extramedullary involvements were observed in the following locations: lung, presacral lymph node, and soft tissue mass lateral to the right maxillary sinus. Among these involvements, higher SUVmax values were observed in the lung and presacral lymph node with [68Ga]FAPI compared to [18F]FDG. However, the soft tissue mass showed a higher SUVmax value in [18F]FDG than [68Ga]FAPI. Conclusions: No significant superiority was observed in [68Ga]FAPI PET/CT over [18F]FDG PET/CT in patients with MM. However, [68Ga]FAPI PET/CT can be utilized as a complementary imaging method to [18F]FDG PET/CT in some settings, especially in low-[18F]FDG affinity and inconclusive cases. Considering the favorable aspects of [68Ga]FAPI PET/CT in MM, such as low background activity, absence of non-specific bone marrow, and physiological brain involvement, further studies with a larger sample size should be conducted.

Pretreatment Serum Levels of IL-1 Receptor Antagonist and IL-4 Are Predictors of Overall Survival in Multiple Myeloma Patients Treated with Bortezomib

Multiple myeloma (MM) is characterized by the malignant proliferation of monoclonal plasma cells in the bone marrow with an elevation in monoclonal paraprotein, renal impairment, hypercalcemia, lytic bony lesions, and anemia. Immune cells and associated cytokines play a significant role in MM growth, progression, and dissemination. While some cytokines and their clinical significance are well described in MM biology, others remain relatively unknown. The present study examines the influence on progression-free survival (PFS) and overall survival (OS) by the serum levels of 27 selected cytokines in 61 newly diagnosed MM patients receiving first-line therapy with bortezomib-based regimens. The measurements were performed using a Bio-Rad Bio-Plex Pro Human Cytokine 27-Plex Assay and a MAGPIX Multiplex Reader, based on the Bio-Plex® 200 System (Bio-Rad). The following levels were determined: IL-1β, IL-1Ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12, IL-13, IL-15, IL-17, Eotaxin, FGF, G-CSF, GM-CSF, IFN-γ, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF-BB, RANTES, TNF-α, and VEGF. Most patients received a VCD chemotherapy regimen (bortezomib, cyclophosphamide, and dexamethasone). In the final multivariate model, IL-13 cytokine level (HR 0.1411, 95% CI: 0.0240-0.8291, p = 0.0302) and ASCT (HR 0.3722, 95% CI: 0.1826-0.7585, p = 0.0065) significantly impacted PFS. Furthermore, ASCT (HR 0.142, 95% CI: 0.046-0.438, p = 0.0007), presence of bone disease at diagnosis (HR 3.826, 95% CI: 1.471-9.949, p = 0.0059), and two cytokine levels-IL-1Ra (HR 1.017, 95% CI: 1.004-1.030, p = 0.0091) and IL-4 (HR 0.161, 95% CI: 0.037-0.698, p = 0.0147)-were independent predictors of OS. Three clusters of MM patients were identified with different cytokine profiles. In conclusion, serum pretreatment levels of IL-13 and IL-4 are predictors of better PFS and OS, respectively, whereas IL-1Ra pretreatment levels negatively impact OS in MM patients treated with bortezomib-based chemotherapy. Cytokine signature profile may have a potential influence on the outcome of patients treated with bortezomib.

Evaluation of prognostic staging systems of multiple myeloma in the era of novel agents

This study aimed to evaluate the existing staging systems for multiple myeloma (MM) in the real world. From January 2010 to June 2019, we retrospectively analyzed 859 newly diagnosed MM patients from two institutions. Clinical data including laboratory findings, imaging examinations and staging system were obtained by reviewing medical records. Survival distributions were estimated using the Kaplan-Meier curve analysis, and Cox proportional hazards model were used to identified risk factors. The overall survival (OS) of eligible patients was 61.0 months. The Revised International Staging System (R-ISS) had a larger receiver operating characteristic curve area (0.603) than both the International Staging System (0.573) and the Durie Salmon staging system (0.567). In the group receiving immunomodulatory agents-based regimens, the median OS was 92.0 months in R-ISS I, 63.0 months in R-ISS II and 18.0 months in R-ISS III (p < 0.0001). In the group receiving proteasome inhibitors-based regimens, the median OS was 102.0 months in R-ISS I, 63.0 months in R-ISS II and 22.0 months in R-ISS III (p < 0.0001). In different subgroups grouped according to age, hemoglobin (HGB), creatinine, and Ca, R-ISS also had a good stratification effect. Patients in R-ISS II, which accounted for 69.9% of all patients, were further analyzed. Univariate and multivariate Cox analyses revealed that age >65 years (p = 0.001), HGB < 100 g/L (p < 0.001), elevated LDH (p = 0.001), and Ca (p = 0.010) were independent predictors of worse prognosis within R-ISS II. To conclusion, R-ISS remains a valuable staging system in the real world of the novel drug era. However, patients classified as R-ISS II still have great heterogeneity.

Predictive Values of PET/CT in Combination With Regulatory B Cells for Therapeutic Response and Survival in Contemporary Patients With Newly Diagnosed Multiple Myeloma

To assess patients with multiple myeloma (MM), the whole-body positron-emission tomography/computed tomography (PET/CT) occupies a pivotal position for diagnostic stratification, response evaluation, and survival prediction, while important limitations are recognized as incapable of representing tumor microenvironment. Regulatory B cells (Bregs) have been reported to have an inhibitory immune function, contributing to bone marrow (BM)-immunosuppressive microenvironment for MM. Therefore, to investigate the role of PET/CT in combination with Bregs’ ratios to predict therapeutic response and survival, we sequentially enrolled 120 patients with newly diagnosed MM (NDMM) who were treated with novel agents in our center, while conventional PET/CT parameters including maximum standard uptake value (SUVmax), ratios of BM-derived Bregs within CD19⁺ B cells, and patients’ clinical characteristics were collected. After a median follow-up of 28.20 months (range 7.00–46.93 months), SUVmax > 4.2 at onset, accounting for 53.2% of NDMM, was uncovered to predict inferior progression-free survival (PFS) as well as overall survival (OS). With regard to the ratios of BM-derived Bregs within CD19⁺ B cells, the cohort with the Bregs’ proportions lower than 10%, accounting for 46.2%, exerted poorer OS. Additionally, the patients with both SUVmax > 4.2 and Bregs’ ratios < 10%, accounting for 31.7%, yielded compromised therapeutic response and long-term survival. Collectively, this study may draw attention on the prognostic value of combination of PET/CT and Bregs’ ratios when clinical decisions are made for MM in the era of novel agents.

A prognostic survival model based on metabolism-related gene expression in plasma cell myeloma

Accurate survival prediction of persons with plasma cell myeloma (PCM) is challenging. We interrogated clinical and laboratory co-variates and RNA matrices of 1040 subjects with PCM from public datasets in the Gene Expression Omnibus database in training (N = 1) and validation (N = 2) datasets. Genes regulating plasma cell metabolism correlated with survival were identified and seven used to build a metabolic risk score using Lasso Cox regression analyses. The score had robust predictive performance with 5-year survival area under the curve (AUCs): 0.71 (95% confidence interval, 0.65, 0.76), 0.88 (0.67, 1.00) and 0.64 (0.57, 0.70). Subjects in the high-risk training cohort (score > median) had worse 5-year survival compared with those in the low-risk cohort (62% [55, 68%] vs. 85% [80, 90%]; p < 0.001). This was also so for the validation cohorts. A nomogram combining metabolic risk score with Revised International Staging System (R-ISS) score increased survival prediction from an AUC = 0.63 [0.58, 0.69] to an AUC = 0.73 [0.66, 0.78]; p = 0.015. Modelling predictions were confirmed in in vitro tests with PCM cell lines. Our metabolic risk score increases survival prediction accuracy in PCM.

Prognostic impact of 18F-FDG PET/CT in patients with multiple myeloma presenting with renal impairment

Renal insufficiency (RI) is a frequent manifestation of multiple myeloma (MM) at time of diagnosis but there is no reliable prognostic factor for patients with MM presenting with RI. This study investigated the prognostic impact of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with MM with RI at diagnosis. The records of 209 patients with MM between June 2011 and November 2018 were retrospectively analyzed. PET/CT positivity was defined as the presence of more than three focal lesions or the presence of extramedullary disease. Of 209 patients, 90 (43.1%) had RI and showed similar survival outcomes to patients who had normal renal function. In total, 113 patients (54.0%) were PET/CT-positive, and 46.6% of patients with RI were PET/CT-positive at baseline. In patients with RI, those who were PET/CT-positive showed significantly inferior survival outcomes to those who were PET/CT-negative [progression-free survival (PFS), 12.7 vs. 34.0 months, P < 0.001; overall survival (OS), 42.2 months vs. not reached, P = 0.001]. On multivariate analysis, PET/CT positivity was significantly associated with PFS and OS in patients with RI. In conclusion, PET/CT is a reliable imaging technique for predicting survival outcomes in patients with MM with RI.

Fluorodeoxyglucose-avid focal lesions and extramedullary disease on 18F-FDG PET/computed tomography predict the outcomes of newly diagnosed symptomatic multiple myeloma patients

PURPOSE

To investigate whether the number of fluorodeoxyglucose (FDG)-avid focal lesions and the presence of extramedullary disease (EMD) on F-FDG PET/computed tomography (PET/CT) can predict the outcomes of newly diagnosed symptomatic multiple myeloma patients.

METHODS

We performed a meta-analysis to research the prognostic significance of focal lesions and EMD on F-FDG PET/CT for overall survival (OS) and progression-free survival (PFS) using a fix-effected model. The PubMed, EMBASE and Cochrane Library databases were searched. Manual searches were also conducted.

RESULTS

Of the 398 citations identified in the original search, 13 original studies with a total of 2823 patients met the inclusion criteria. The pooled hazard ratios of focal lesions were 1.63 [95% confidence interval (CI) 1.41-1.86, P = 0.442, I= 0%] for PFS and 2.15 (95% CI 1.74-2.57, P = 0.615, I= 0%) for OS. The pooled hazard ratios of EMD were 1.89 (95% CI 1.44-2.34, P = 0.497, I= 0%) for PFS and 1.91 (95% CI 1.08-2.73, P = 0.182, I= 29.6%) for OS. The results of the subgroup analysis showed the same trend. No significant heterogeneity was observed among studies.

CONCLUSION

This meta-analysis demonstrated that patients with a higher number of FDG-avid focal lesions and EMD on PET/CT may experience a higher risk for progression and a shorter survival time than those with a few focal lesions and no EMD.

Prognostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in newly diagnosed multiple myeloma: a systematic review and meta-analysis

OBJECTIVES

We performed a systematic review and meta-analysis on the prognostic values of ¹⁸F-FDG PET/CT in patients with newly diagnosed multiple myeloma (MM).

METHODS

PubMed and Embase were searched until July 10, 2019, for studies that reported the prognostic significance of ¹⁸F-FDG PET in patients with newly diagnosed MM, with overall (OS) and progression-free survival (PFS) included as outcomes. Hazard ratios (HRs) and their 95% confidence intervals (CIs) were meta-analytically pooled using a random-effects model.

RESULTS

Fifteen studies (1670 patients) were included for qualitative synthesis. Among multiple PET parameters, the presence of extramedullary disease (EMD), more than three focal lesions (FLs), and high FDG uptake were widely evaluated and significantly associated with shorter OS and PFS in most of the included studies. Among 11 studies included in quantitative synthesis, the overall HRs of EMD, more than three FLs, and high FDG uptake on PFS were 2.12 (95% CI, 1.52-2.96), 2.38 (95% CI, 1.84-3.07), and 2.02 (95% CI, 1.51-2.68), respectively. The pooled HRs of those three parameters on OS were 2.37 (95% CI, 1.77-3.16), 3.29 (95% CI, 2.38-4.56), and 2.28 (95% CI, 1.67-3.13). No statistical differences were found across parameters for either PFS (p = 0.6822) or OS (p = 0.2147).

CONCLUSIONS

Pretreatment ¹⁸F-FDG PET/CT is a significant predictor for disease progression and survival in patients with MM. It may be a useful prognostic biomarker capable of accurate risk stratification and application in clinical decision-making for newly diagnosed MM.

KEY POINTS

• There remain unmet clinical needs for reliable prognostic biomarkers in patients with newly diagnosed multiple myeloma. • This meta-analysis shows that the presence of extramedullary disease, more than three focal lesions, and high FDG uptake from baseline ¹⁸F-FDG PET are significant prognostic factors. • These imaging biomarkers might help the accurate stratification of patient prognosis which is required for choosing an appropriate therapeutic strategy in clinical practice.

Frontline therapy for newly diagnosed patients with multiple myeloma

Since the introduction of an alkylator to the treatment of multiple myeloma (MM), new effective agents have been developed, such as immunomodulatory drugs including thalidomide, lenalidomide, and pomalidomide; proteasome inhibitors including bortezomib, carfilzomib, and ixazomib; monoclonal antibodies including daratumumab and elotuzumab; and deacetylase inhibitors including panobinostat. Numerous regimens with these new agents have been developed and they have contributed in improving survival outcomes in MM patients. In addition, the recommended therapies for newly diagnosed MM change every year based on the results of clinical trials. This review will discusses the appropriate induction therapies based on recent clinical trials for patients with newly diagnosed MM.

Chemokine receptor-4 targeted PET/CT with 68Ga-Pentixafor in assessment of newly diagnosed multiple myeloma: comparison to 18F-FDG PET/CT

PURPOSE

¹⁸F-FDG PET/CT has some limitations in the evaluation of multiple myeloma (MM). Since chemokine receptor-4 is overexpressed in MM, we perform a prospective cohort study to compare the performance of ⁶⁸Ga-Pentixafor and ¹⁸F-FDG PET/CT in newly diagnosed MM.

METHODS

Thirty patients with newly diagnosed MM were recruited. All patients underwent ⁶⁸Ga-Pentixafor and¹⁸F-FDG PET/CT within 1 week after enrollment. A positive PET/CT was defined as the presence of focal PET-positive lesions in bone marrow or diffuse bone marrow patterns (uptake > liver). Bone marrow uptake values in ⁶⁸Ga-Pentixafor and¹⁸F-FDG PET/CT (total bone marrow glycolysis [TBmG_FDG], total bone marrow uptake with ⁶⁸Ga-Pentixafor [TBmU_CXCR4], total bone marrow volume [TBmV], SUVmean, and SUVmax) were obtained by drawing total bone marrow volume of interest on PET/CT. The positive rates of the PET/CT scans were statistically compared, and the correlation between quantitative bone marrow uptake values and clinical characteristics, laboratory findings, and staging was analyzed.

RESULTS

⁶⁸Ga-Pentixafor PET/CT had a higher positive rate than ¹⁸F-FDG PET/CT in recruited patients (93.3 vs. 53.3%, p = 0.0005). In quantitative analysis, bone marrow uptake values in ⁶⁸Ga-Pentixafor (TBmU_CXCR4, SUVmax, and SUVmean) were positively correlated with end organ damage, staging, and laboratory biomarkers related to tumor burden including serum β2-microglobulin, serum free light chain, and 24-h urine light chain (p < 0.05). In ¹⁸F-FDG PET/CT, only the SUVmean of total bone marrow was positively correlated with serum free light chain and 24-h urine light chain (p < 0.05).

CONCLUSIONS

⁶⁸Ga-Pentixafor PET/CT is promising in assessment of newly diagnosed MM.

TRIAL REGISTRATION NUMBER

NCT03436342.

Imaging and bone marrow assessments improve minimal residual disease prediction in multiple myeloma

The value of minimal residual disease (MRD) status by bone marrow and imaging analysis as independent prognostic factors has been well established in multiple myeloma (MM). Nevertheless data about their potential complementarity for a more accurate assessment are limited. With this aim, we retrospectively analyzed the prediction of outcome with the combination of PET-CT and MRD, assessed by multiparameter flow cytometry (MFC) in 103 patients with newly diagnosed MM. We confirmed the benefit in terms of progression-free survival (PFS), linked to the achievement of negativity by MFC (hazard ratio [HR] 0.53; 95% confidence interval [CI]: 0.28-0.98), and PET-CT (HR 0.18; 95% CI: 0.09-0.36) individually. By combining both techniques, patients who became MRD-/PET-, with a median of PFS 92 months, had significant prolonged median PFS (P < .001). This is compared with MRD+/PET- and PET+ patients (median PFS of 45 and 28 months, respectively). We observed a significant difference (P = .003) in overall survival (OS) outcomes between MRD-/PET- and MRD+/PET- patients (4-year OS 94.2% and 100%, respectively), vs PET+ patients (4-year OS 73.8%). All survival results were confirmed in a conditional landmark analysis. These findings support the potential complementarity between PET-CT and MFC, and highlight their better predictive capability when improving sensitivity.

Medullary Abnormalities in Appendicular Skeletons Detected With 18F-FDG PET/CT Predict an Unfavorable Prognosis in Newly Diagnosed Multiple Myeloma Patients With High-Risk Factors

OBJECTIVE. The prognostic value of medullary abnormalities in the appendicular skeleton (AS) of patients with multiple myeloma (MM) has recently been suggested. However, functional evaluation of these abnormalities using PET/CT has not been investigated to date. This study aimed to explore the prevalence and prognostic relevance of AS medullary abnormalities depicted by PET/CT in patients with MM. MATERIALS AND METHODS. This retrospective study included 228 consecutive patients with newly diagnosed, symptomatic MM who were treated with novel agents. All patients underwent pretreatment ¹⁸F-FDG PET/CT. RESULTS. There were 157 (68.9%) patients with zero AS focal lesions, 33 (14.5%) with one to three AS focal lesions, and 38 (16.7%) with more than three AS focal lesions on pre-treatment PET/CT. Patients with more than three AS focal lesions showed significantly shorter progression-free survival (PFS) and overall survival (OS) than did those with fewer lesions (both, p < 0.001). In multivariate analysis, the presence of more than three AS focal lesions remained prognostic for both PFS and OS (both, p < 0.001). Furthermore, the presence of more than three AS focal lesions discriminated patients with both significantly shorter PFS and significantly shorter OS even among patients with established high-risk parameters, including high-risk cytogenetic abnormalities, advanced disease stage, and established high-risk PET/CT findings. CONCLUSION. The presence of more than three focal lesions in the AS on pretreatment PET/CT was an independent predictor of poor survival in patients with newly diagnosed MM. Remarkably, this finding discriminated patients with shorter survival from among those with established high-risk factors. Evaluation of findings in the AS may complement and improve the prognostic performance of known stratification systems as well as PET/CT.

Interest of Pet Imaging in Multiple Myeloma

The interest of 18Fluoro-deoxyglucose (FDG) positron emission tomography (PET) imaging in the management of patients with multiple myeloma (MM) for the workup at diagnosis and for therapeutic evaluation has recently been demonstrated. FDG-PET is a powerful imaging tool for bone lesions detection at initial diagnosis with high sensitivity and specificity values. The independent pejorative prognostic value on progression-free survival (PFS) and overall survival (OS) of baseline PET-derived parameters (presence of extra-medullary disease (EMD), number of focal bone lesions (FLs), and maximum standardized uptake values [SUV_max]) has been reported in several large independent prospective studies. During therapeutic evaluation, FDG-PET is considered as the reference imaging technique, because it can be performed much earlier than MRI which lacks specificity. Persistence of significant FDG uptake after treatment, notably before maintenance therapy, is an independent pejorative prognostic factor, especially for patients with a complete biological response. So FDG-PET and medullary flow cytometry are complementary tools for detection of minimal residual disease before maintenance therapy. However, the definition of PET metabolic complete response should be standardized. In patients with smoldering multiple myeloma, the presence of at least one hyper-metabolic lytic lesions on FDG-PET may be considered as a criterion for initiating therapy. FDG-PET is also indicated for initial staging of a solitary plasmacytoma so as to not disregard other bone or extra-medullary localizations. Development of nuclear medicine offer new perspectives for MM imaging. Recent PET tracers are willing to overcome limitations of FDG. (11)C-Methionine, which uptake reflects the increased protein synthesis of malignant cells seems to correlate well with bone marrow infiltration. Lipid tracers, such as Choline or acetate, and some peptide tracers, such as (68) Ga-Pentixafor, that targets CXCR4 (chemokine receptor-4, which is often expressed with high density by myeloma cells), are other promising PET ligands. 18F-fludarabine and immuno-PET targeting CD138 and CD38 also showed promising results in preclinical models.

Pretreatment 18F-FDG PET/CT combined with quantification of clonal circulating plasma cells as a potential risk model in patients with newly diagnosed multiple myeloma

PURPOSE

Both ¹⁸F-FDG PET/CT and clonal circulating plasma cell (CPC) quantification are emerging tools for multiple myeloma (MM) prognostication that have been validated in recent studies. This study investigated the value of PET/CT coupled with CPC quantification for MM prognostication that may contribute to future risk-adapted treatment.

METHODS

We retrospectively analysed the prognostic relevance of a combination of pretreatment PET/CT findings and CPC levels in 163 consecutive patients with newly diagnosed, symptomatic MM receiving novel agents during induction therapies.

RESULTS

High-risk PET/CT findings and elevated CPC levels were defined by the presence of >3 focal lesions with or without extramedullary disease and CPCs ≥0.10% of the total mononuclear cells evaluated, respectively. Subsequently, patients were divided into three groups: PET-CPC stage I included patients with no high-risk PET/CT findings and low CPC levels; stage III included patients with high-risk PET/CT findings and high CPC levels; and stage II included the remaining patients. The three groups of patients differed significantly in terms of both progression-free survival (PFS) and overall survival (OS) (median PFS: not reached [NR] and 36.4 and 15.9 months, and median OS: NR, NR, and 40.4 months for stages I, II, and III, respectively; P < 0.001 for both PFS and OS). This system discriminated both PFS and OS even among younger (age < 75 years) or older (≥ 75 years) patients, patients with Revised International Staging System stage II or III, and patients with or without high-risk cytogenetic characteristics. In the multivariate analysis, the PET-CPC staging system remained prognostic for both PFS and OS.

CONCLUSIONS

The PET-CPC staging system predicted survival outcomes independently of established risk factors in patients with newly diagnosed MM. Pretreatment ¹⁸F-FDG PET/CT assessment combined with CPC quantification may improve the prognostication of MM and facilitate the development of novel risk-adapted approaches for MM.

Contemporary patient-tailored treatment strategies against high risk and relapsed or refractory multiple myeloma

Recurrence of disease due to chemotherapy drug resistance remains a major obstacle to a more successful survival outcome of multiple myeloma (MM). Overcoming drug resistance and salvaging patients with relapsed and/or refractory (R/R) MM is an urgent and unmet medical need. Several new personalized treatment strategies have been developed against molecular targets to overcome this drug resistance. There are several targeted therapeutics with anti-MM activity in clinical pipeline, including inhibitors of anti-apoptotic proteins, monoclonal antibodies, antibody-drug conjugates, bispecific antibodies, fusion proteins, and various cell therapy platforms. For example, B-cell maturation antigen (BCMA)-specific CAR-T cell platforms showed promising activity in heavily pretreated R/R MM patients. Therefore, there is renewed hope for high-risk as well as R/R MM patients in the era of personalized medicine.