Clinical and survival analysis of nasopharyngeal carcinoma with consistently negative Epstein-Barr virus DNA.

BACKGROUND: To assess the clinical and survival features of nasopharyngeal carcinoma (NPC) with consistently negative Epstein-Barr virus (EBV) DNA level. METHODS: Propensity score matching (PSM) method was used to create well-balanced cohorts. Kaplan-Meier method and Cox proportional hazards models were performed to conduct survival analysis. RESULTS: Four hundred and eighty patients were enrolled. Patients with consistently negative plasma EBV DNA level had a greater chance to present a relatively earlier T and N classification compared with those with positive EBV DNA level (p < .001; p = .015). And patients with consistently negative EBV level were significantly associated with preferable 3-year DFS (95.0% vs. 84.4%, p = .004), DMFS (98.3% vs. 89.4%, p = .009), and OS (100% vs. 97.6%, p = .004). CONCLUSIONS: NPC patients with consistently negative EBV DNA level performed an earlier clinical stage and negative EBV DNA level was related to preferable survival outcomes.