Prognostic significance of volume-based metabolic parameters by 18F-FDG PET/CT in thymic epithelial tumor

1928 Objectives The aim of this study was to investigate the prognostic value of volume-based metabolic parameters by 18F-FDG PET/CT in thymic epithelial tumor compared with other prognostic parameters. Methods Subjects were 71 consecutive patients (mean age, 51 ± 13 y) who were initially diagnosed thymic epithelial tumor undergoing 18F-FDG PET/CT between April 2003 and November 2009. Various metabolic or volume-based PET parameters of primary tumors including maximum and average standardized uptake value (SUVmax, SUVavg), metabolic tumor volume (MTV), total lesion glycolysis (TLG) were measured. Survival analysis for disease-free survival or progression-free survival was performed by using Kaplan-Meier method using PET parameters and other clinical variables including age, sex, Masaoka stage, histopathology, treatment modality. For determining independent prognostic factors, Cox regression analysis was done. Results Of the 71 patients, 20 had low-risk thymomas, 22 had high-risk thymomas, and 29 had thymic carcinomas. Recurrence or disease progression occurred in 23 patients (32%). Mean clinical follow-up period was 26 ± 20 m. In univariate analysis, age (p Conclusions In thymic epithelial tumor, TLG, a volume-based metabolic parameter is a significant independent prognostic factor for disease-free survival or progression-free survival