EVALUATION ON THE PROGNOSIS OF NASOPHARYNGEAL CARCINOMA AFTER RADIOTHERAPY BY QUANTITATIVE ANALYSIS OF CELL-FREE EPSTEIN-BARR VIRUS DNA IN PLASMA

[Objective]To explore the evaluation on the prognosis of nasopharyngeal carcinoma(NPC)after radiotherapy by quantitative analysis of cell-free epstein-barr virus dna in plasma.[Methods]50 patients with preliminary diagnosis nasopharyngeal carcinoma were study group,and 50 healthy persons were healthy control group,and 20 patients with pate carcinoma except NPC were case control group. Quantitative real time polymerase chain reaction was used to detect the Epstein-Barr Virus(EBV)DNA in plasma,and the patients with NPC were all followed up after radiotherapy. All the data was statistically analyzed.[Results]The positive rate of cell-free EBV-DNA in plasma of NPC was 84.0%(42/50),and the positive rate of cell-free EBV-DNA in plasma of healthy person was 10.0%(42/50),and the cell-free EBV-DNA in plasma of pate carcinoma was negative(0/20). The positive rate of cell-free EBV-DNA in plasma of NPC was significantly higher than those of the rest groups(P﹤0.01). The positive rate of cell-free EBV-DNA in plasma of NPC preradiotherapy was significantly higher than those of the postradiotherapy and healthy persons(P﹤0.001),while there was no significant different level and positive rate between NPC preradiotherapy and healthy persons(P = 0.243;P = 0.262). After radiotherapy,the EBV-DNA in plasma were positive in 12 patients,and 8 of them with recurrence and metastasis(local recurrence 5 cases,lung metastasis 2 cases and bone metastasis 1 case)6 months after radiotherapy. The rest 38 NPC patients with negative EBV-DNA in plasma,7 cases occurred recurrence and metastasis 6 months after radiotherapy.[Conclusion]EBV-DNA in plasma is of a high rate expression in NPC patints,and it is a useful indicator to monitor the recurrence and metastasis after radiotherapy.