A clinical study of induction chemotherapy±concurrent chemoradiotherapy for stage N2-3M0 nasopharyngeal carcinoma with plasma Epstein-Barr virus DNA>4000 copies/ml

Abstract

Objective To investigate the value of induction chemotherapy in the treatment of stage N2-3M0 nasopharyngeal carcinoma with plasma Epstein-Barr virus (EBV) DNA>4000 copies/ml. Methods A retrospective study was performed on clinical data from 210 patients with stage N2-3M0 nasopharyngeal carcinoma and plasma EBV DNA>4000 copies/ml who were admitted to our hospital from 2009 to 2013. In the 210 patients, 101 received induction chemotherapy plus concurrent chemoradiotherapy (NCRT) and 109 concurrent chemoradiotherapy alone (CCRT). The survival rates were calculated by the Kaplan-Meier method. The log-rank test was used for the analysis of survival rates and univariate analysis of the impacts of the changes in the plasma EBV DNA level after induction chemotherapy on the prognosis. Results The 3-year sample size was 154.The NCRT group had significantly higher 3-year disease-free survival (DFS) and distant metastasis-free survival (DMFS) rates than the CCRT group (80.1% vs. 70.6%, P=0.029; 87.1% vs. 76.0%, P=0.036), while there was no significant difference in 3-year overall survival (OS) rate between the two groups (88.0% vs. 80.4%, P=0.210). Patients with stage N2 disease in the NCRT group had significantly higher 3-year DFS and DMFS rates than those in the CCRT group (P=0.031, 0.014). Patients with stage N3 disease in the NCRT group had significantly higher 3-year OS, DFS, and DMFS rates than those in the CCRT group (P=0.029, 0.012, 0.019). In all the patients, the 3-year OS and DMFS rates were improved with the increase in the cycle number of induction chemotherapy (P=0.020, 0.021). In the NCRT group, patients treated with 2, 3, and 4 cycles of induction chemotherapy before radiotherapy had plasma EBV-DNA clearance rates of 51.85%, 76.92%, and 88.57%, respectively (P=0.004). Using the complete clearance of plasma EBV-DNA as a predictor of progression, the sensitivity for the above three groups was 62.50%, 66.67% and 75.00(P=0.910), respectively, and the specificity was 57.89%, 90.00% and 96.77%(P=0.000), respectively. Conclusions In the treatment of nasopharyngeal carcinoma with plasma EBV DNA>4000 copies/ml, induction chemotherapy improves DFS and DMFS in patients with stage N2-3M0 disease and OS in patients with stage N3 disease; induction chemotherapy dose not improve recurrence-free survival rate. The prognosis and plasma EBV DNA clearance rate are improved with the increase in the cycle number of induction chemotherapy. Using the complete clearance of plasma EBV DNA as a predictor of progression, the sensitivity and specificity in patients treated with 4 cycles of chemotherapy are superior over those in patients treated with 2 or 3 cycles of chemotherapy. Key words: Nasopharyngeal neoplasms/induction chemotherapy; Nasopharyngeal neoplasms/concurrent chemo-radiotherapy; Epstein-Barr virus; Deoxyribonucleic acid