Potential pitfalls in incorporating plasma Epstein-Barr virus DNA in the management of nasopharyngeal carcinoma.

BACKGROUND: This study identifies potential pitfalls in incorporating plasma Epstein-Barr virus (EBV) DNA into the management of nasopharyngeal carcinoma (NPC). METHODS: A total of 208 NPC patients without distant metastasis who received radical treatment and had measurements of EBV DNA at baseline, 8 weeks and 26 weeks postradiotherapy were analyzed. Prognostic and predictive values at each time-point were compared. RESULTS: Risk stratification by pretreatment level failed to identify a poor prognostic group. Detectable EBV DNA at 8 weeks and 26 weeks postradiotherapy were both associated with significantly poorer 5-year disease-free survival (HR 0.30, P < .001 and HR 0.03, P < .001, respectively) and overall survival (HR 0.27, P = .009 and HR 0.03, P < .001, respectively). Eighty percentage had detectable EBV DNA at recurrence (53.3% for local only, 100% for regional only, and 100% for distant failure). CONCLUSIONS: Posttreatment EBV DNA, particularly at 26 weeks post-radiotherapy, has high prognostic and predictive values. Surveillance endoscopy/imaging are recommended for the detection of local recurrence.