ABSTRACT
Objective To evaluate the prognostic value of serial 18F-fluorodeexyglucose (FDG) PET/CT in patients with nasopharyngeal carcinoma (NPC).Methods Thirty-seven NPC patients who had 18F-FDG PET/CT scan before and after external beam intensity-modulated radiotherapy, were studied retrospectively.All patients were followed for five years.Correlation analysis between metabolic tumor volume (MTV)/uptake volume index (UVI) and survival was performed by Kaplan-Meier analysis, Log-rank test and multivariate Cox model.Results The 5-year overall survival (OS) and disease-free survival (DFS) rates were 70.3% (26/37) and 62.2% ( 23/37 ), respectively.Patients with a lower MTV (MTV＜30 cm3) had significantly higher 5-year OS ( 82.6% ( 19/23 ) ) and DFS (73.9% ( 17/23 )) rates than those with a higher MTV (OS:50.0% (7/14),x2 =5.28, P＜0.05; DFS:42.9% (6/14),x2 =4.84, P＜0.05).Patients with a lower UV1 (UVI＜150) had significantly higher 5-year OS( 87.5%( 21/24 )) and DFS (79.2% (19/24)) rates than those with a higher UVI (OS:38.5% (5/13),x2 =10.72, P＜0.01;DFS:30.8% (4/13), x2 =11.04, P＜0.01).Multivariate analysis showed that UVI and metabolic response (MR) were independent predictors of DFS.Conclusions Tumor volume parameters, UVI and MR, are independent prognostic factors for patients with NPC.Patients with a high UVI may benefit from more aggressive treatment.