Prognostic significance of Epstein-Barr virus viral load in patients with T1-T2 nasopharyngeal cancer.

Nasopharyngeal cancer (NPC) is highly prevalent in southern Chinese populations but it is rare in most parts of the world. A few studies were performed in nonendemic regions of the world, and suggested the prognostic value of Epstein-Barr virus (EBV) DNA load in blood. In this study, EBV DNA presence and viral load (VL) level in the blood of patients with NPC in Polish population were presented. In addition, its prognostic value for locoregional control among other clinicopathological features was evaluated. Patients with carcinoma of the nasopharynx treated definitively with radiotherapy or radiochemotherapy were included in the study. Real-time polymerase chain reaction was performed for quantitating of EBV DNA in plasma. Among patients with NPC, 51% (22 of 43) were classified as EBV-positive with the mean of the VL of 4934 +/- 8693 copies/mL. Multiple regression analysis between log EBV DNA VL and clinical parameters revealed that the most important factors increasing the VLs were advanced N disease together with no-smoking status and advanced T tumors. Multivariate Cox regression analysis revealed that T3-T4 tumors were an independent prognostic factor for poor locoregional control. Analysis for the subgroup of patients with T1-T2 tumors showed that T1-T2 EBV-negative patients had better locoregional control compared with T1-T2 EBV-positive, though without statistical significance. In conclusion, it seems that EBV DNA determination may have an important role in diagnostics of patients with NPC with T1-T2 tumors indicating a subgroup with poorer prognosis, though it needs to be proven on a larger cohort.