Pretreatment 18F-FDG PET/CT texture parameters provide complementary information to Epstein-Barr virus DNA titers in patients with metastatic nasopharyngeal carcinoma

The aim of the present study was to evaluate whether texture features extracted from 18F-FDG PET/CT images may provide additional prognostic information in patients with metastatic nasopharyngeal carcinoma (NPC). We retrospectively examined 52 patients with metastatic NPC who underwent assessment of EBV DNA titers and pretreatment 18F-FDG PET/CT imaging. All participants were followed up for at least two years. The following 18F-FDG PET parameters were analyzed: standardized uptake value (SUV), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and texture parameters. Independent predictors of outcomes were identified using receiver operating characteristic curve analysis and multivariate Cox proportional hazards models. On multivariate analysis, EBV DNA titers > 3500 copies/mL and TLG of metastatic lesions > 138 mL were identified as independent predictors of overall survival (OS) (P = 0.036 and P = 0.047, respectively). Patients were divided into two subgroups based on their EBV DNA titers (high versus low). In the high EBV DNA titer group, a lower homogeneity of distant metastatic lesions and higher TLG values of distant metastatic lesions were independent risk factors for OS (P = 0.033 and P < 0.001, respectively). In the low EBV DNA titer group, a reduced uniformity of distant metastatic lesions and a higher SUVmax of distant metastatic lesions were unfavorable risk factors for OS (P = 0.004 and P = 0.005, respectively). Based on these results, we devised two prognostic scoring systems for the prediction of 2-year OS in each EBV DNA titer group. Some of the PET-derived texture parameters are independent predictors of outcomes in patients with metastatic NPC and provide complementary information to EBV DNA titers.