Induction chemotherapy followed by concurrent chemoradiotherapy versus concurrent chemoradiotherapy alone in stage III-IVb nasopharyngeal carcinoma patients with Epstein-Barr virus DNA ≥4000 copies/ml: a matched study

BACKGROUND: The effects of induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CCRT) in high-risk (stage III-IVb with EBV DNA≥4000 copies/ml) nasopharyngeal carcinoma (NPC) patients are unclear. METHODS: A total of 325 high-risk NPC patients treated with IC+CCRT or CCRT alone who were treated with intensity-modulated radiation therapy (IMRT) between March 2007 and March 2013 were included. For each patient in the IC+CCRT group, a matched pair in the CCRT group was matching for: gender, age, T stage, N stage, clinical stage and WHO (World Health Organization) type. The primary endpoint was overall survival (OS), and the secondary endpoints were progression-free survival (PFS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRFS). RESULTS: There were no significant differences in OS, PFS, DMFS, and LRFS between the IC+CCRT (148 patients) and CCRT (177 patients) groups. After matching, 103 paired patients were analyzed, and there were no differences between the IC+CCRT and CCRT groups regarding clinical outcomes. Based on the subgroup analysis of 156 very-high-risk patients (stage N2-3 with EBV DNA ≥4000 copies/ml), the 5-year OS of the IC+CCRT and CCRT groups was 84.3% and 67.5% (P =0.033), respectively. Based on our multivariate analysis, the treatment group was significantly associated with OS (P=0.034; HR0.451, 95%CI 0.216-0.941). CONCLUSIONS: IC+CCRT did not improve the clinical outcomes of high-risk NPC patients compared to CCRT alone. However, in very-high-risk patients, IC+CCRT treatment led to increased OS compared to patients received CCRT treatment alone.