Optimal cumulative cisplatin dose in nasopharyngeal carcinoma patients based on plasma Epstein-Barr virus DNA level after induction chemotherapy.

PURPOSE: This study aimed to elucidate the optimal cumulative cisplatin dose (CCD) for concurrent chemoradiotherapy (CCRT) according to the post-induction chemotherapy (IC) plasma Epstein-Barr virus (EBV) DNA level. RESULTS: EBV DNA was detected and undetected in 179 and 370 patients, respectively. Of the entire cohort, 73/549 (13.3%) patients received a total CCD >/= 160 mg/m(2) and 476/549 (86.7%) patients, <160 mg/m(2). CCD enhancement was not associated with a survival benefit in patients with undetected EBV DNA after IC. However, among patients with post-IC detectable EBV DNA, higher 3-year PFS and locoregional relapse-free survival (LRFS) rates were observed in those who received a CCD >/= 160 mg/m(2). Multivariate analysis also showed CCD was an independent prognostic factor for PFS and LRFS in patients with post-IC detectable EBV DNA. CONCLUSIONS: CCD enhancement was not associated with a survival benefit in patients with undetected EBV DNA after IC. However, among patients with post-IC detectable EBV DNA, those receiving >/=160 mg/m(2) CCD showed significantly improved 3-year PFS and LRFS. METHODS: NPC patients (549) treated with IC and CCRT were included. Prognosis was assessed using a multivariate Cox proportional hazards model. Furthermore, grade 1-4 toxicities were compared between different CCD groups.