Prognostic role of plasma Epstein-Barr virus DNA load for nasopharyngeal carcinoma: A meta-analysis

Abstract

Purpose: Predicting prognosis and treatment outcomes for patients with for nasopharyngeal carcinoma (NPC) has been difficult due to the heterogeneous nature of the disease This study aimed to evaluate pretreatment copy number of plasma Epstein-Barr virus (EBV) DNA as an outcome marker for survival in NPC. Methods: MEDLINE, CENTRAL and Embase databases were searched until April 7, 2015. Included studies were randomized controlled trials, two-arm prospective studies, or retrospective studies in patients with newly diagnosed NPC. The primary outcome was overall survival and secondary outcomes were progression-free, relapse-free, disease-free and distant metastasis-free survival. Sensitivity, quality and publication bias assessments were performed. Results: Sixteen studies were included in the meta-analysis, with a total of 7698 patients. For overall survival, pooled HR was 3.005 (95% confidence interval [CI] = 2.245-4.022; P < 0.001), indicating that higher levels of EBV DNA were associated with a greater risk of death. Pooled estimates for relapse-free, disease-free, progression-free and distant metastasis-free survival indicated that higher levels of EBV DNA were associated with an increased risk of relapse, disease recurrence, disease progression and distant metastasis in comparison with lower levels of EBV DNA (P values < 0.001). Conclusion: This meta-analysis found that high EBV DNA levels indicate poor prognosis and reduced long-term survival in patients with newly diagnosed NPC; hence, EBV DNA levels are highly prognostic of survival in patients with NPC. None of the included studies used the WHO standard for EBV DNA measurement, indicating a greater need for harmonization in future studies.