The value of cervical node features in predicting long-term survival of nasopharyngeal carcinoma in the intensity-modulated radiotherapy era

Abstract

Objective: To investigate the prognostic value of cervical node features in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT) and build a prognostic nomogram to predict the long-term survival. Methods: In this study, 1752 patients after IMRT from 2008 to 2011 were recruited. The clinical and laboratory characteristics and the nodal features including the nodal number, maximum 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 established to predict survival. Results: The 10-year distant metastases-free survival (DMFS) and disease-specific survival (DSS) rates were 86.5% and 80.8%, respectively. Multivariate analysis showed that age, sex, lactate dehydrogenase (LDH), CNN, ENE, T stage, and N stage were independent factors for DSS. Two nomograms—nomogram A (without nodal features) and nomogram B (with nodal features)—were built. The calibration curve for the probability of DSS showed good agree-ment between prediction by nomogram and the actual observation. The C-index of nomo-gram B was higher than that for nomogram A in predicting DSS (0.708 vs 0.676, P<0.01). Conclusion: The nodal features including ENE and CNN were negative prognostic factors for NPC, and the prognostic nomogram incorporating the nodal features was more accurate in predicting survival than the nomogram without nodal features.