Relative Tumor Volume Is A Better Independent Prognostic Factor In Advanced Nasopharyngeal Carcinoma

Objectives: To evaluate the prognostic effect of relative tumor volume in patients with advanced nasopharyngeal carcinoma(NPC)treated with concurrent chemoradiotherapy.Materials and Methods: Between Jan 1,2009 and December30,2012,143 patients diagnosed with NPC in UICC stage III–IVb by histopathology were enrolled in the study.These patients underwent intensity-modulated radiotherapy combined concurrent chemotherapy.The tumor volume automatically reconstructed a three-dimensional image according to the planning system.RGTV was calculated based on GTV/person’s volume;RGTVnx was calculated based on GTVnx/person’s volume;RGTVnd was calculated based on GTVnd/person’s volume.Results: In receiver operator operating characteristic curve analysis,2.38、1.091 and 0.273 were determined as the cut-off points for RGTV、RGTVnx and RGTVnd,respectively.The 5-year OS,DFS,DMFS and LRFS rates for patients with a RGTV>2.38 vs.RGTV≤2.38 was 46.1% vs.95.8%(P<0.001),42.5%vs.97.0%(P<0.001)、52.8% vs.98.0%(P<0.001),72.7% vs.98.0%(P<0.001),respectively,for RGTVnx>1.091 vs.RGTVnx≤1.091 was 65.4% vs.93.4%(P<0.001),65.2% vs.94.8%(P<0.001),71.4% vs.97.4%(P<0.001),and84.8% vs.97.3%(P=0.003),respectively,for RGTVnd >0.273 vs.RGTVnd≤0.273 was 70.3% vs.96.5%(P<0.001),70.1% vs.94.8%(P<0.001),77.5% vs.98.2%(P<0.001),88.5% vs.96.6%(P=0.049),respectively.Conclusion: Relative tumor volume was an independent prognostic factor for NPC that might improve the current NPC TNM classification system and provide new clinical evidence for personalized treatment strategies.