Individualized concurrent chemotherapy by pretreatment plasma Epstein‐Barr viral DNA in II‐III stage nasopharyngeal carcinoma: A propensity score matching analysis using a large cohort

OBJECT: To ascertain the treatment effect of concurrent chemotherapy (CCT) in stage II‐III nasopharyngeal carcinoma (NPC) patients with different Epstein‐Barr virus (EBV) DNA level in intensity‐modulated radiotherapy (IMRT) era. METHODS: A total of 2742 patients diagnosed with stage II‐III NPC were involved in this study. Patients received IMRT with/without CCT. Overall survival (OS) was the primary endpoint. Receiver operating characteristics curve was used to determine the cut‐off value of pre‐DNA based on OS. After propensity score matching, the role of CCT was explored in patients with different EBV DNA level. RESULTS: In our cohort, the cut‐off value of pre EBV DNA was 1460 copies/mL (area under curve [AUC], 0.695‐0.769; sensitivity, 0.766; specificity, 0.599). Patients with high EBV DNA level showed poor survival in OS, progression free survival (PFS), locoregional relapse‐free survival (LRFS) and distant metastasis‐free survival (DMFS). In patients with EBV DNA level >1460 copies/mL, the concurrent chemoradiotherapy (CCRT) group achieved higher 3‐year OS compared with IMRT groups. However, the CCRT and IMRT groups showed comparable OS in patients with EBV DNA ≤1460 copies/mL. In multivariate analyses, CCT was a protective factor for OS, PFS, and LRFS in high‐risk patients (EBV DNA level >1460 copies/mL), while not an independent prognostic factor among the low‐risk patients (EBV DNA level ≤1460 copies/mL). CONCLUSION: Pre‐EBV DNA could be a useful tool to guide individualized treatment for stage II‐III NPC patients. Additional CCT to IMRT improved the survival for patients with high pre‐EBV DNA, while those with low pre‐EBV DNA could not.