The Prognostic Value of Plasma Epstein-Barr Viral DNA and Tumor Response to Neoadjuvant Chemotherapy in Advanced-Stage Nasopharyngeal Carcinoma

Purpose: To explore the prognostic value of the plasma load of Epstein-Barr viral (EBV) DNA and the tumor response to neoadjuvant chemotherapy (NACT) in advanced-stage nasopharyngeal carcinoma (NPC). Patients and Methods: In all, 185 consecutive patients with stage III to IVb NPC treated with NACT followed by concurrent chemoradiation therapy (CCRT) were prospectively enrolled. The primary endpoint was progression-free survival (PFS), and the secondary endpoints included locoregional relapseefree survival (LRFS) and distant metastasisefree survival (DMFS). Results: EBV DNA was detected in 165 (89%) patients before treatment but was undetectable in 127 (69%) patients after NACT. Detectable EBV DNA levels after NACT were correlated with poor prognosis (3-year PFS 71.8% vs 85.2%, P = .008 and 3-year DMFS 82.5% vs 92.3%, P = .013). An unsatisfactory tumor response (stable disease or disease progression) after NACT was also correlated with poor clinical outcome (3-year PFS 71.1% vs 85.9%, P = .005 and 3-year LRFS 82.7% vs 93.5%, P = .012). Multivariate analysis showed that the EBV DNA level after NACT (hazard ratio [HR] 2.31, 95% CI 1.18-4.54, P = .015) and the tumor response to NACT (HR 2.84, 95% CI 1.42-5.67, P = .003) were both significant prognostic factors for PFS. Multivariate analysis also showed that EBV DNA after NACT was the only significant predictor of DMFS (HR 2.99, 95% CI 1.25-7.15, P = .014) and that tumor response to NACT was the only significant predictor of LRFS (HR 3.31, 95% CI 1.21-9.07, P = .020). Conclusion: Detectable EBV DNA levels and an unsatisfactory tumor response (stable disease or disease progression) after NACT serve as predictors of poor prognosis for patients with advanced-stage NPC. These findings will facilitate further risk stratification, early treatment modification, or both before CCRT. (C) 2015 Elsevier Inc. All rights reserved.