Prognostic impact of circulating Epstein-Barr virus (EBV) DNA concentration and EBV serology in 125 extranodal NK/T cell lymphoma, nasal type (ENKL) patients

extranodal NK/T cell lymphoma, nasal type (ENKL) has worse efficacy and prognosis than B-NHL. Circulating EBV DNA concentration can reflect the efficacy and prognosis in some EBV related malignance (nasopharyngeal carcinoma). But there are few studies about the relation between EBV infection and ENKL. This prospective study is to confirm predictive value of circulating EBV DNA concentration and EBV serology in ENKL patients.

In the prospective study, serum samples from 125 previously untreated ENKL patients were collected from Jan 2002 to Dec 2006. We detect VCA-IgA and EA-IgA level by immunoenzyme methods and circulating EBV DNA concentration by real-time PCR assay. All patients were received long-term efficacy and survival assessment.

The median follow-up time is 4.53 years. The positive rates of VCA ƒüIgA and EA ƒüIgA are 30.6% and 1.6% respectively, both of which could not predict the efficacy and survivals. The positive rate of circulating EBV DNA is 69.4%, with a median concentration of 13400 copies/ml. Patients with extranodal involvement, B syndrome, upper respiratory involvement, neutropenia or anemia or thrombocytopenia, liver dysfunction, and increasing of β₂MG, have significantly higher EBV DNA positive rate(45.1% A54.4% A62.3% A53.5% A90.0% A59.3%, respectively). Patients in higher EBV DNA concentration group is easier to have bone and/or skin involvement (≤13400 copies/ml group: 45.8%vs. >13400 copies: 16.0%, p=0.024). The positive circulating EBV DNA group has a lower complete remission (CR) rate (38.8%vs.59.2%, p=0.026), higher relapse rate (52.6%VS.26.7%, p=0.046) than negative one. The 5-year DFS and 5-year OS decreased with the dose of circulating EBV DNA group (DFS: negative group74.3% vs. ≤13400 copies/ml group 55.0% vs. >13400 copies/ml group 28.6%, p=0.003; OS: negative group 55.8% vs. ≤13400 copies/ml group 48.4% vs. >13400 copies/ml group 29.2%, p=0.004).

The positive rate of circulating EBV DNA is much higher in ENKL. Circulating EBV DNA concentration, as measured by real-time PCR, is a useful tumor marker for diagnosis and prognostication with ENKL patients. Patients with higher dose of circulating EBV DNA level (>13400 copies/ml) may undergo more aggressive biological behavior.

No relevant conflicts of interest to declare.