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Aim: To compare the effects of high-dose therapy (HDT consisting of high-dose chemotherapy followed by autologous stem cell transplantation) and conventional-dose chemotherapy (non-HDT) on the uptake of 18F-sodium fluoride (NaF) in the whole bone, pelvis, and femoral neck of multiple myeloma (MM) patients. Method: The data of 19 MM patients who received HDT (61.5 (SD 5.6) years) and 11 MM patients who received conventional-dose chemotherapy (70.9 (SD 7.2) years) were collected in a prospective study. NaF PET/CT imaging was performed at baseline, and 8 weeks and 2 weeks after treatment for the HDT group and the non-HDT group, respectively. A CT-based algorithm was applied to segment the bones, and the global mean SUV (GSUVmean) of the whole bone and pelvis was calculated (OsiriX MD v.9.0, Pixmeo SARL; Bernex, Switzerland). In addition, regions of interest for the whole, medial, and lateral femoral neck were delineated bilaterally. Whole bone and pelvis measurements were replicated by two observers. Results: The average GSUVmean in the whole bone and pelvis of the patients who underwent HDT significantly decreased from before to after treatment (− 16.27%, p = 0.02 and − 16.54%, p = 0.01, respectively). A significant decrease in the whole and lateral femoral neck was also observed bilaterally in the HDT group. No significant decrease in average GSUVmean was observed in the non-HDT group. A high level of inter-observer reliability was found in intra-class correlation (ICC for pre-treatment whole bone 0.983, post-treatment whole bone 0.989, pre-treatment whole pelvis 0.998, post-treatment whole pelvis 0.996). Conclusion: NaF uptake significantly decreased after treatment in patients who received high-dose therapy. A high level of agreement was observed between two operators for whole bone and pelvis measurements. [ABSTRACT FROM AUTHOR]

Several risk scores for disease progression in patients with smoldering multiple myeloma ( SMM) have been proposed; however, all have been developed using single-center registries. To examine risk factors for time to progression ( TTP) to multiple myeloma ( MM) for SMM, we analyzed a nationwide population-based cohort of 321 patients with newly diagnosed SMM registered within the Danish Multiple Myeloma Registry between 2005 and 2014. Significant univariable risk factors for TTP were selected for multivariable Cox regression analyses. We found that both an M-protein ≥30 g/L and immunoparesis significantly influenced TTP ( HR 2.7, 95% CI (1.5;4.7), P = 0.001, and HR 3.3, 95% CI (1.4;7.8), P = 0.002, respectively). High free light chain ( FLC) ratio did not significantly influence TTP in our cohort. Therefore, our data do not support recent IMWG proposal of identifying patients with FLC ratio above 100 as having ultra high-risk of transformation to MM. Using only immunoparesis and M-protein ≥30 g/L, we created a scoring system to identify low-, intermediate-, and high-risk SMM. This first population-based study of patients with SMM confirms that an M-protein ≥30 g/L and immunoparesis remain important risk factors for progression to MM. [ABSTRACT FROM AUTHOR]

The practical application of dual-time-point-imaging (DTPI) technique still remains controversial. One of the issues is that current parameters of DTPI quantification suffer from some deficiencies, mainly limited sampling of the diseased sites by confining measurements to specific locations. We aimed to examine the correlation between the percent change from early to delayed scans in whole-bone marrow (WBM) 18 F-FDG uptake, as measured by a CT-based method of PET/CT quantification, and response to treatment in multiple myeloma (MM) patients. Pre-treatment 18 F-FDG-PET/CT scans of 36 newly diagnosed MM patients were collected in a prospective study at 1 h and 3 h post tracer injection (NCT02187731). A threshold algorithm based on bone Hounsfield units on CT was applied to segment and quantify WBM 18 F-FDG uptake. Patients were separated into two treatment groups: high-dose therapy with autologous stem cell transplant (HDT) and non-high dose therapy (non-HDT). The International Response Criteria for MM patients was used to determine each patient's response to treatment. In the HDT group, WBM 18 F-FDG uptake increased significantly in patients that had a poor response to treatment, from a median of 1.31 (IQR: 1.13-1.64) at 1 h to a median of 1.85 (1.45-2.10) at 3 h. The median percent change was 37.77% (IQR: 23.47-46.4), with a range of 6.10-50.73 ( P = 0.003). However, no significant change in uptake was observed in patients with a complete response ( P = 0.24). The same trend was observed for the non-HDT group. WBM uptake of 18 F-FDG assessed with dual-time-point imaging may have a role in predicting treatment response in MM., Competing Interests: None., (AJNMMI Copyright © 2020.)

Focal bone lesions and fractures due to weakened bone are associated with higher morbidity and mortality of multiple myeloma (MM) patients. 18 F-sodium fluoride ( 18 F-NaF) is a sensitive PET radiotracer for detection of abnormal bone metabolism and, therefore, is particularly suited to assess the degree of bone involvement in MM patients. We aimed to investigate the prognostic significance of metabolic active volume (MAV) of 18 F-NaF-avid lesions in MM patients. In addition to MAV, conventional methods of PET quantification, namely SUVmean and SUVmax, were measured in each patient for the purpose of comparison. Thirty-seven newly diagnosed MM patients were included. PET imaging was performed after intravenous administration of 200 MBq NaF. Active bone lesions and fractures on whole-body 18 F-NaF-PET/CT scans were identified. An adaptive thresholding algorithm automatically calculated the total MAV, SUVmean and SUVmax for each patient (ROVER, ABX, Radeberg, Germany). The patients were followed for a median of 39.8 months after treatment (range: 17.8-55.4). The overall survival (OS) of patients with 18 F-NaF-MAV value > 38.65 (36.36% [N of Events/Total N: 4/11]) was significantly shorter than that of patients with 18 F-NaF-MAV value < 38.65 (3.85% [1/26]; P = 0.002). In multivariate forward stepwise (conditional LR) Cox regression analysis of prognostic factors of OS (including 18 F-NaF-MAV (> 38.65 or < 38.65), age, gender, beta-2 microglobulin, and revised international staging system), 18 F-NaF-MAV remained the only significant factor (HR: 14.39, P = 0.02). The results for PFS were not significant. Moreover, Kaplan-Meier analyses of conventional methods of PET quantification did not reveal any statistically significant log-rank p -values. MM patients with high 18 F-NaF-MAV had shorter overall survival, compared to those with low 18 F-NaF-MAV levels (NCT02187731)., Competing Interests: None., (AJNMMI Copyright © 2020.)