Prognostic Significance of 18F-FDG PET Parameters and Plasma Epstein-Barr Virus DNA Load in Patients with Nasopharyngeal Carcinoma

UNLABELLED: The plasma concentration of Epstein-Barr virus (EBV) DNA is associated with tumor burden and prognosis in patients with nasopharyngeal carcinoma (NPC), but data on the relationship between viral load and (18)F-FDG PET functional parameters are lacking. We examined the association of (18)F-FDG PET functional parameters and EBV DNA load with the clinicopathologic characteristics and clinical outcomes of patients with NPC. METHODS: One hundred eight patients with NPC who underwent (18)F-FDG PET before treatment were included in this study. We determined total lesion glycolysis (TLG) of the primary tumor, the cervical nodes, and their combination and the maximal standardized uptake value of the primary tumor and cervical lymph nodes. EBV DNA was measured by real-time polymerase chain reaction. RESULTS: EBV DNA was significantly associated with total TLG (R(2) = 0.589). Total TLG values had the highest correlation with EBV DNA load and were significantly associated with tumor, nodal, and overall stages. However, tumor TLG greater than the median (>65 g) was the only parameter significantly associated with overall, local recurrence-free, disease-free, and distant metastasis-free survivals (P = 0.033, 0.014, <0.001, and 0.023, respectively). After allowance for potential confounders, tumor TLG retained its independent significance for overall and disease-free survival rates (P = 0.045 and 0.006, respectively). CONCLUSION: Total TLG values are primarily associated with tumor burden and clinical stage, whereas tumor TLG is the best predictor of patient survival after treatment.