Figure 2.

High pre-treatment levels of EBV-DNA are associated with increased risk or relapse and mortality. Stratification analyses of the survival of NPC patients. All NPC patients were stratified according to pre-treatment plasma EBV-DNA levels. The NPC relapse and mortality rates were then calculated. Subsequently, the RFS and OS periods of individual groups of patients were estimated by the Kaplan-Meier method and analyzed by the log-rank test. (A) Percentages of patients with relapse, (B) mortality, (C) RFS and (D) OS throughout the observation period in the two patient groups. EBV, Epstein-Barr virus; NPC, nasopharyngeal carcinoma; RFS, relapse-free survival; OS, overall survival.