INTRODUCTION: The aim was to evaluate the prognostic values of pretreatment 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) parameters for predicting local failure in nasopharyngeal carcinoma (NPC) patients in the intensity-modulated radiotherapy (IMRT) era. METHODS: Retrospective analysis was performed on 759 patients with NPC who underwent pretreatment 18F-FDG PET. The optimal cutoff values for maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) were determined by receiver operating characteristic curve analysis. Univariate and multivariate analysis was performed to identify the prognostic factors influencing local failure-free survival (LFFS). Survival curves for the different risk groups were plotted using the Kaplan-Meier survival analysis method and compared using the log-rank test. RESULTS: The median follow-up period was 49.0 months (range: 3.0-118.0 months). The optimal cutoff of SUVmax and MTV were 7.44 and 22.21 mL, respectively. Patients with higher SUVmax and MTV were associated with worse LFFS. The survival curves of different groups were significantly separated. The univariate analysis showed the statistical significance of SUVmax, MTV, and their composite in LFFS (p = 0.002 for SUVmax
p = 0.002 for MTV
p <
0.002 for their composite). The multivariate analysis showed that higher SUVmax and MTV was an independent negative prognostic factor for LFFS (HR = 1.805, 95% CI: 1.004-3.245, p = 0.049). The subgroups of stages III-IV further confirmed the impact of SUVmax and MTV on LFFS (HR = 1.884, CI: 1.087-3.708, p = 0.026). CONCLUSION: Patients with higher SUVmax and MTV were associated with local failure as well as in the III-IV advanced stage.