J Cancer 2016; 7(6):664-670. doi:10.7150/jca.14183
Circulating EBV DNA, Globulin and Nodal Size Predict Distant Metastasis after Intensity-Modulated Radiotherapy in Stage II Nasopharyngeal Carcinoma
1. Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Department of Radiation Oncology, Guangzhou 510060, China;
2. Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, No. 74 Zhongshan Road, Guangzhou 510060, China.
Du XJ, Tang LL, Mao YP, Guo R, Sun Y, Lin AH, Ma J. Circulating EBV DNA, Globulin and Nodal Size Predict Distant Metastasis after Intensity-Modulated Radiotherapy in Stage II Nasopharyngeal Carcinoma. J Cancer 2016; 7(6):664-670. doi:10.7150/jca.14183. Available from http://www.jcancer.org/v07p0664.htm
Background: The optimal treatment for early-stage nasopharyngeal carcinoma (NPC) remains controversial. Identification of prognostic factors for metastasis and tumor progression is urgently required to improve clinical decision-making for patients with American Joint Committee on Cancer (AJCC) 2009 stage II NPC from the endemic area.
Methods: Consecutive newly-diagnosed patients (n=296) with non-disseminated, biopsy-proven stage II NPC were retrospectively reviewed; all patients received intensity-modulated radiotherapy and MRI follow-up. Plasma EBV DNA level, serum lactate dehydrogenase, serum albumin, serum globulin and leukocyte counts were measured before therapy. Survival rates were analyzed using the Kaplan-Meier method and log-rank test and multivariate Cox proportional hazards model.
Results: Median follow-up was 50.2 months (range, 8-69.5 months). Multivariate analysis demonstrated a plasma Epstein-Barr virus (EBV) DNA level ≥ 4000 copies/mL, maximal axial diameter (MAD) of the cervical lymph nodes ≥ 30 mm and serum globulin level < 29.5 g/L were independent predictors of poor DMFS (P = 0.018; P = 0.019; P = 0.006, respectively). On the basis of these parameters, a prognostic model was developed as follows: 1) patients with no risk factors; 2) one risk factor; and 3) two or three risk factors. The 3-year distant metastasis-free survival rates for groups 1, 2 and 3 were 100%, 94.6% and 84.3%, respectively (P = 0.001).
Conclusion: The prognostic model based on EBV DNA, serum globulin and nodal size may facilitate individualized treatment of patients with stage II NPC at high risk of distant metastasis.
Keywords: prognostic model, Epstein-Barr virus DNA, serum globulin, nodal size, metastasis, nasopharyngeal carcinoma.