The Value of Cervical Node Features in Predicting Long-Term Survival of Nasopharyngeal Carcinoma in Intensity-Modulated Radiotherapy Era

The prognostic value of cervical node features in nasopharyngeal carcinoma(NPC) patients treated with intensity-modulated radiotherapy (IMRT) was controversial. In this study, about 1752 patients after IMRT from 2008 to 2011 were recruited. The nodal features including the nodal number, maximize dimension diameter, extranodal extension(ENE)and cervical node necrosis(CNN) were retrospective analyzed. Univariate Cox and multivariate proportional hazard regression models were used to test the prognostic value of nodal features. Prognostic nomograms were built to predict the survival. The 10-year distant metastases free survival (DMFS) and disease-specific survival(DSS) rates were 86.5% and 80.8%. By multivariate analysis, the independent factors for the DSS were gender, age, lactate dehydrogenase (LDH), CNN, ENE, T stage and N stage. Nomogram A (without nodal features ) and nomogram B (with nodal features) were built. The calibration curve for the probability of DSS showed good agreement between prediction by nomogram and actual observation.The C-index of nomogram B was higher than for nomogram A in predicting DSS ( 0.708 vs 0.676,P <.01). These results demonstrated the nodal features including the ENE and CNN were negative prognostic factors in patients with NPC, and the prognostic nomogram incorporating the nodal features was more accurate.