Prognostic value of circulating Epstein-Barr virus DNA level post-induction chemotherapy for patients with nasopharyngeal carcinoma: A recursive partitioning risk stratification analysis

Abstract

BackgroundTo evaluate the prognostic value of plasma Epstein-Barr virus (EBV) DNA level post-induction chemotherapy (IC) for patients with nasopharyngeal carcinoma (NPC). MethodsA total of 893 newly diagnosed NPC patients treated with IC were retrospectively reviewed. The recursive partitioning analysis (RPA) was performed to construct a risk stratification model. The receiver operating characteristic (ROC) analysis was applied to determine the optimal cut-off value of post-IC EBV DNA. ResultsPost-IC EBV DNA levels and overall stage were independent predictors for distant metastasis-free survival (DMFS), overall survival (OS), and progression-free survival (PFS). The RPA model base on post-IC EBV DNA and overall stage categorized the patients into three distinct risk groups: RPA I (low-risk: stage II-III and post-IC EBV DNA < 200 copies/mL), RPA II (median-risk: stage II-III and post-IC EBV DNA ≥ 200 copies/mL, or stage IVA and post-IC EBV DNA < 200 copies/mL), and RPA III (high-risk: stage IVA and post-IC EBV DNA ≥ 200 copies/mL), with 3-year PFS of 91.1%, 82.6%, and 60.2%, respectively (p < 0.001). The DMFS and OS rates in different RPA groups were also distinct. The RPA model showed better risk discrimination than either the overall stage or post-RT EBV DNA alone. ConclusionsPlasma EBV DNA level post-IC was a robust prognostic biomarker for NPC. We developed an RPA model that provides improved risk discrimination over the 8th edition of the TNM staging system by integrating the post-IC EBV DNA level and the overall stage.