The role of pretreatment FDG standard uptake value in predicting for clinical outcome in locally advanced nasopharyngeal carcinoma / 中华放射肿瘤学杂志

ABSTRACT

ObjectiveTo explore the prognostic value of pretreated maximum standardized uptake value (SUVmax) using 18-fluorodeoxyglucose positron emission tomography with computed tomography (18FDG PET/CT) in locally-advanced nasopharyngeal carcinoma (NPC) treated by intensity-modulated radiotherapy (IMRT).MethodsOne hundred and forty previously untreated stage Ⅲ - Ⅳb ( UICC/AJCC 6th) patients with biopsy-proven nasopharyngeal carcinoma were examined.All of the enrolled patients accepted whole body/head-neck 18FDG PET/CT before radical IMRT. 18FDG uptakes were recorded as SUVmax of primary tumor (SUVmax-P) and SUVmax of cervical lymph nodes (SUVmax-N).The relationships between SUVmax and long-term clinical outcomes were analyzed.ResultsThe median SUVmax-P was 10.4,and the median SUVmax-N was 6.2.The SUVmax-P was weakly correlated with T-stage ( R =0.279,P =0.001 ).The SUVmax-N was weakly correlated with N stage ( R =0.334,P =0.000 ).There were no difference of the median SUVmax-P (9.2 vs.10.4,U =560.50,P =0.805 ) and the median SUVmax-N (4.0vs.5.0,U =576.00,P =0.908) between patients with and without local recurrence.The median SUVmax-P of patients with distant metastasis was significantly higher than those without metastasis (11.9 vs.9.8,U =987.50,P =0.014).The SUV of 10.2 was taken as a cut-off for high and low uptake tumors.For patients with SUVmax-P ＞ 10.2,the 5-year distant metastasis-free survival (DMFS) and 5-year overall survival (OS)were significantly higher than those with SUVmax-P ≤ 10.2 (69.1％ vs.95.5％,x2 =15.88,P =0.000;68.4％ vs.94.0％,x2 =15.56,P =0.000,respectively).Multivariate analysis showed that SUVmax-P was the only independent risk factor of 5-year DMFS and OS ( HR =7.87,P =0.001 and HR =5.14,P =0.003). Conclusion SUVmax-P is a useful biomarker predicting long-term clinical outcomes in newly diagnosed locally-advanced NPC patients.