Predictive value of therapeutic monitoring with plasma Epstein-Barr virus DNA in Extranodal NK/T cell lymphoma, nasal type

Predictive value of therapeutic monitoring with plasma Epstein-Barr virus DNA in Extranodal NK/T cell lymphoma, nasal type

Background: Predictive tumor markers are essential for extranodal NK/T cell lymphoma, nasal type (ENKTL), which pursues an aggressive clinical course with poorer prognosis. This prospective study was conducted to evaluate the dynamic monitoring value of circulating EBV DNA concentration for the prediction of ENKL during treatment.

Method: Patients with untreated, centrally reviewed diagnosis of ENKTL were included in our study. Plasma Epstein-Barr virus (EBV) DNA levels were collected before and/or every 2 cycles of chemotherapies for circulating EBV DNA measurement by a real-time PCR assay.

Result: From Jan 2002 to Aug 2012, 113 newly diagnostic ENKTL patients enrolled. The positive rate of circulating EBV DNA is 61.9% (70/113) with a median concentration of 1.21×103copies/ml. Patients who had initial positive circulating EBV-DNA had more lymph nodes invasion, higher IPI and KPI score. The more advance of the stage, the higher rate of the circulating EBV-DNA positive. When divided the positive group as low and high-dose ones by the cut-off value as 2×104copies/ml, the CR rate of the high-dose group is much lower and the 5-year OS is significantly better than the low-dose group and the negative group. After two cycles of chemotherapy, 45 patients were tested circulating EBV-DNA and 53.33% (24/45) patients became negative EBV-DNA candidates. There were 87.5% (21/24) patients obtained complete remission at the end of the treatment, comparing as 42.86% (9/21) in the still positive EBV-DNA groups(P= 0.002). There is a tendency that the patients whose circulating EBV-DNA become negative after two cycles will have better prognosis (5-year OS: 75% vs 46%, P=0.074). The similar situation of CR rate and OS happened in the EBV-DNA detection of completion of total chemotherapy. 7 of 13 relapsed pts of ＞1×103copies/ml EBV-DNA at the time of recurrent, and the survival outcome was dismal for them compared to the other 6 pts of ≤1×103copies/ml（5- year OS: 0% vs 80%, P=0.001）

Conclusion: Circulating EBV-DNA level can predict the efficacy of treatment as a dynamic marker of ENKL. Patients with early positive detection of EBV-DNA after 2 cycles of chemotherapy maybe received more aggressive treatments.