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.