This study aimed to evaluate the prognostic value of combining pretreatment Epstein-Barr virus (EBV) DNA level and cervical node necrosis (CNN) for patients with nasopharyngeal carcinoma (NPC) receiving intensity-modulated radiotherapy (IMRT). A total of 607 incident nonmetastatic NPC patients treated with IMRT ± chemotherapy were reviewed. Patients were divided into four groups based on EBV DNA level and CNN status. The primary endpoint was progression-free survival (PFS). Kaplan-Meier curves with log-rank test were applied to compare survival outcomes and the Cox proportional model was used to identify independent prognostic factors. Pretreatment EBV DNA level and CNN status were independent prognostic factors. Patients in the low-level EBV DNA group or non-CNN group had significantly better 5-year PFS. Multivariate analyses demonstrated that CNN was an independent prognostic factor for overall survival (OS) (HR = 1.927, 95% CI: 1.129-3.290, P = .016), PFS (HR = 1.492, 95% CI: 1.005-2.214, P = .047), distant metastasis-free survival (DMFS) (HR = 1.661, 95% CI: 1.044-2.644, P = .032), but not locoregional relapse-free survival. EBV DNA levels correlated significantly with CNN with a correlation coefficient of .324 (P < .001). Compared with low-level EBV DNA and non-CNN grouping, high-level EBV DNA and CNN grouping had poor PFS. The combined classification was an independent prognostic factor for OS (P < .001), PFS (P = .001), and DMFS (P = .018). Pretreatment plasma EBV DNA level and CNN status both closely correlated with prognosis of NPC patients in the IMRT era. Combined EBV DNA level and CNN status improves risk stratification and prognostic value.
Keywords: EBV; cervical node necrosis; cohort; nasopharyngeal carcinoma.
© 2019 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.