Prognostic Significance of Volume-based Metabolic Parameters by ¹⁸F-FDG PET/CT in Gallbladder Carcinoma

Purpose: We investigated the prognostic values of volume-based metabolic parameters by ¹⁸F-fluorodeoxyglucose ( ¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) in gallbladder carcinoma patients and compared them with other prognostic parameters. Materials and Methods: We enrolled 44 patients, who were initially diagnosed with gallbladder carcinoma and undergoing ¹⁸F-FDG PET/CT. Various metabolic volume-based PET parameters of primary tumors, including maximum and average standardized uptake values (SUV _max, SUV _avg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), were measured in gallbladder carcinoma patients using mediastinal blood pool activity as a threshold SUV for determining the tumor boundaries. Overall survival analysis was performed using the Kaplan-Meier method with PET parameters and other clinical variables. For determining independent prognostic factors, Cox proportional hazards regression analysis was performed. Results: Of the 44 enrolled patients, cancer- or treatment-related death occurred in 30 (68. 2 %). The mean clinical follow-up period was 22. 2 ± 10. 4 m (range, 0. 6-35. 9 m). Univariate analysis demonstrated that clinical or pathologic TNM stage (P < 0. 001), treatment modality (P < 0. 001), MTV (cutoff = 135 cm ³, P = 0. 001), and TLG (cutoff = 7,090, P < 0. 05) were significant prognostic factors. In multivariate analysis, both clinical or pathologic TNM stage [hazard ratio (HR) = 2. 019 (I vs II), 21. 287 (I vs III), and 24. 354 (I vs IV); P = 0. 001) and TLG (HR = 2. 930; P < 0.05) were independent prognostic factors for predicting overall survival. Conclusions: In gallbladder cancer, TLG of the primary tumor, a volume-based metabolic parameter, is a significant independent prognostic factor for overall survival in conjunction with the clinical or pathological TNM stage.