Combined pre-treatment and middle-treatment Epstein-Barr virus DNA load contributes to prognostication and treatment modification in nasopharyngeal carcinoma patients.

Abstract

To investigate whether pre-treatment and middle-treatment plasma Epstein-Barr virus (EBV) DNA loads are useful predictors of prognosis and indicators of therapy modification in nasopharyngeal carcinoma (NPC) patients undergoing radical concurrent chemoradiotherapy (CCRT). Plasma EBV DNA load was measured by quantitative polymerase chain reaction before treatment (pre-DNA) and during the second cycle of DDP (mid-DNA). The primary endpoint was 5-year progression-free survival (PFS). A total of 775 NPC patients treated with CCRT were included. In total, 553 patients with pre-DNA <4000 copies/mL and 222 with ⩾4000 copies/mL. A total of 559 patients had mid-DNA undetectable and 216 had detectable. Multivariate analysis showed that pre- and mid-DNA were independent prognostic predictors of PFS [hazard ratio (HR), 2.035; 95% confidence interval (CI), 1.406-2.944; p < 0.001; HR, 1.597; 95% CI, 1.101-2.316; p = 0.014]. The area under the curve of the combination of pre-DNA and mid-DNA for 5-year PFS was higher than that of pre-DNA, mid-DNA, and tumor node metastasis (TNM) stage (0.679 versus 0.622, 0.608, 0.601). In the low-risk group (pre-DNA <4000 copies/mL and undetectable mid-DNA), patients receiving ⩽200 mg/m2 showed similar efficacy as those receiving >200 mg/m2 cumulative cisplatin dose (CCD) but were associated with fewer all-grade late toxicities. However, in the high-risk group (pre-DNA ⩾4000 copies/mL or detectable mid-DNA), patients receiving >200 mg/m2 CCD showed a higher 5-year PFS (73.1% versus 58.6%, p = 0.027) and locoregional relapse-free survival (88.5% versus 76.1%, p = 0.028) than those receiving ⩽200 mg/m2 CCD. The combination of pre-DNA and mid-DNA could be particularly useful for guiding risk stratification and early treatment modification for NPC treated with CCRT. A total of 200 mg/m2 cisplatin seemed to be the optimal dose for the low-risk patients, while >200 mg/m2 cisplatin may be adequate to achieve satisfactory survival outcomes in the high-risk group.