The Role of Epstein-Barr Virus DNA Load and Serology as Screening Tools for Nasopharyngeal Carcinoma.

ABSTRACT

OBJECTIVE: Screening for nasopharyngeal carcinoma (NPC) among family members has been advocated in endemic populations in view of significantly increased risks. We aimed to compare the role of Epstein-Barr virus (EBV) DNA load and EBV IgA serology as tools for screening patients with a first-degree family history of NPC. STUDY DESIGN: Case-control study. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Serum samples were compared from 293 newly diagnosed NPC patients and 475 individuals with a first-degree family history of NPC. EBV DNA load was measured by real-time quantitative polymerase chain reaction, while EBV viral capsid antigen (VCA) IgA and EBV early antigen (EA) IgA titers were measured by immunofluorescence assays. RESULTS: NPC patients had a significantly higher median EBV DNA load as compared with unaffected family members (835.4 vs 18.8 copies/mL; P < .001). At 100 copies/mL, EBV DNA load demonstrated a sensitivity of 76.8% and a specificity of 85.6%. A positive EBV-EA IgA titer (≥110) gave a sensitivity of 85.0% and a specificity of 96.4%. There was good correlation between EBV DNA load and EBV serology titers (Spearman's ρ = .536 and .594 for EBV-VCA IgA and EBV-EA IgA, respectively; P < .001). Receiver operating characteristic analysis demonstrated that EBV-VCA IgA and EBV-EA IgA were better classifiers than EBV DNA load (areas under the curve 0.942, 0.926, and 0.880, respectively) in distinguishing NPC patients and unaffected family members. CONCLUSION: EBV DNA load and EBV IgA serology demonstrate good sensitivity and specificity as screening tools. EBV-EA IgA gave the best sensitivity and specificity profile as a screening tool for NPC among high-risk family members.