RT Journal Article SR Electronic T1 11C-acetate PET/CT predicts 4-year overall survival for patients with newly diagnosed myeloma JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 657 OP 657 VO 56 IS supplement 3 A1 Chen, Sirong A1 Cheung, William A1 Cheng, Kam Chau A1 Leung, Yim Lung A1 Wong, Ka-Nin A1 Chim, CS A1 Ho, Chi-Lai YR 2015 UL http://jnm.snmjournals.org/content/56/supplement_3/657.abstract AB 657 Objectives We previously reported that 11C-acetate (ACT) PET/CT is a surrogate imaging marker for metabolic measurement of tumor burden in multiple myeloma (MM). We have prospectively extended our investigation on how this marker could be used to predict the 4-year overall survival (OS) in newly diagnosed MM patients.Methods From Oct 2009 to Dec 2010, 20 patients (M:13, F:7; mean age=67.0±11.0y) were newly diagnosed of active MM when referred for pretreatment 11C-ACT and 18F-FDG PET/CT. Diagnosis was by hematological and histological proof, and all had pretreatment serum β2-microglobulin (b2m) level measured within 1 mo before PET/CT. They were followed for a minimum of 4 years or till death. Focal bone lesions (FBLs) were visually assessed on PET. SUVmax of L3 was chosen as the index site to represent generalized marrow activity (GMA) for quantitative assessment of diffuse MM. Kaplan-Meier univariate analysis was used to evaluate the prognostic significance of b2m level and PET/CT parameters including GMA of 11C-ACT, GMA of 18F-FDG, no. of 11C-ACT-avid FBLs and no. of 18F-FDG-avid FBLs. The threshold of significant prognostic factor for the prediction of 4-y OS was defined by ROC analysis.Results Of these 20 MM patients (13 stage I, 3 stage II, 4 stage III by International Staging System), 11C-ACT PET/CT was positive in 18 (90%) and 18F-FDG in 12 (60%). No patient showed extramedullary lesions. During 4 years of follow-up, 8/20 (40%) patients died. Univariate analysis of the above mentioned parameters identified 2 predictors statistically significant for 4-y OS in these patients: 1. pretreatment GMA on 11C-ACT PET/CT (median OS>4 y vs. 30 mo for GMA≤5 & >5, P<0.05); 2. pretreatment serum b2m level (median OS>4 y vs. 30 mo for b2m≤4.22 & >4.22 ug/ml, P<0.05).Conclusions 11C-ACT PET/CT has a high sensitivity for detection of active disease in treatment-naïve MM patients, a prerequisite condition for monitoring of treatment. Pretreatment GMA>5 on 11C-ACT PET/CT might predict a poor 4-y OS.