RT Journal Article
SR Electronic
T1 <sup>11</sup>C-acetate PET/CT has a significantly higher correlation with FISH test than <sup>18</sup>F-FDG PET/CT in risk stratification of multiple myeloma
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 20
OP 20
VO 60
IS supplement 1
A1 Ho, Chi-Lai
A1 Chen, Sirong
A1 Cheung, William
A1 Leung, Yim Lung
A1 Cheng, Kam Chau
A1 Wong, Ka Nin
A1 Wong, Yuet Hung
A1 Wu, Kwan Kit
A1 Liang, Hin Suen Raymond
YR 2019
UL http://jnm.snmjournals.org/content/60/supplement_1/20.abstract
AB 20Objectives: FISH (fluorescence in situ hybridization test) is the most common genetics test for multiple myeloma (MM), capable of risk stratification, prediction of disease progression, and management decision for patients with smoldering MM (SMM) and MM. We previously reported that 11C-acetate PET/CT is a continuum surrogate imaging marker for the detection of active MM lesions and measurement of MM tumor burden. In this prospective study, we aim to extend our investigation on 11C-acetate PET/CT for risk stratification of newly diagnosed MM patients by correlation study with MM FISH results. Methods: From Oct 2013 to July 2018, 104 newly identified MM patients (M: 57, F: 47; age range: 33-89 y, mean: 63.7±11.5 y) were referred to dual-tracer (11C-acetate &amp; 18F-FDG) PET/CT for treatment planning. The diagnosis was confirmed by bone marrow biopsy with evidence of abnormal plasma cell &gt;=10%. Interphase TARGET FISH test was performed for detection of 4 chromosome aberrations: 17p13.1 (p53) deletion, t(4;14) translocation, t(14;16) translocation and chromosome lq21 (CKS1B) amplification of the plasma cells on marrow blood samples. Detection positive for any of the 4 chromosome aberrations was considered “high-risk MM”, otherwise “low-risk MM”. PET/CT was analyzed on focal bone lesions (FBL) and marrow activity (semi-quantified by SUVmax of L3 for plasma cell burden). Kaplan-Meier univariate analysis was used to evaluate the predictive significance in MM risk stratification of 4 PET/CT parameters: 1. number of FBL by 11C-acetate, 2. number of FBL by 18F-FDG, 3. marrow activity of 11C-acetate, 4. marrow activity of 18F-FDG. ROC analysis was performed on the significant risk predictors to define the cut-off values for high-risk MM. Results: The reported plasma cell infiltration by bone marrow examination ranged from 11 to 95% (mean=(43±24)%). Marrow activity (SUVmax_L3) of 11C-acetate, as imaging indicator for MM tumor burden, showed a strong correlation with plasma cell infiltration (r=0.723, P&lt;0.05), whereas 18F-FDG marrow activity showed a weak correlation (r=0.539, P&lt;0.05). TARGET FISH analysis identified 56/104 high-risk and 48/104 low-risk MM. Univariate analysis of the above mentioned 4 PET/CT parameters identified 2 predictors statistically significant for high-risk MM: 1. SUVmax_L3 of 11C-acetate, which was significantly higher in high-risk versus low-risk MM (SUVmax_L3=5.53±2.20 vs 3.79±1.31, P=0.0001); 2 SUVmax_L3 of 18F-FDG, also significantly different between high-risk and low-risk MM (SUVmax_L3=3.27±1.53 vs 2.48±0.90, P=0.01). For prediction of high-risk MM, ROC-defined thresholds of SUVmax_L3 were 4.45 and 3.15 on 11C-acetate and 18F-FDG PET, respectively. Nevertheless, 11C-acetate PET was significantly more sensitive than 18F-FDG (76.8% vs 46.4%, P&lt;0.05). In the 30/56 high-risk MM patients negative on 18F-FDG PET, 17/30 (56.7%) were identified by 11C-acetate and the incremental value was significant (P&lt;0.05). The specificity and AUC for identifying high-risk MM were 83.3% (40/48) vs 81.3% (39/48), and 0.818 vs 0.673 by 11C-acetate and 18F-FDG PET. Conclusions: Our data suggested that metabolic characterization with 11C-acetate PET on the assessment of Acetyl CoA synthase activity in MM plasma cells was able to assess MM tumor burden as well as to identify high-risk MM patients significantly more accurate than with 18F-FDG. The 11C-acetate marrow activity threshold (&gt;=4.45) may serve as an imaging biomarker for risk stratification in treatment-naïve MM patients, and hopefully may facilitate treatment planning.