Figure 3.

Detection of post-treatment EBV-DNA in NPC patients indicates a poor prognosis. Stratification analyses of the survival of NPC patients. All NPC patients were stratified according to the detection of post-treatment plasma EBV-DNA. 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 relapse, (B) mortality, (C) RFS and (D) OS throughout the observation period in the two groups of patients. EBV, Epstein-Barr virus; NPC, nasopharyngeal carcinoma; RFS, relapse-free survival; OS, overall survival.