Early circulating EBV-DNA clearance predicts enhanced short-term treatment response and survival benefit in locally advanced nasopharyngeal carcinoma.

BACKGROUND AND PURPOSE: This study investigates the correlation between the clearance of circulating Epstein-Barr virus DNA (cEBV-DNA) and treatment outcomes in locally advanced nasopharyngeal carcinoma (laNPC) patiePnts. MATERIALS AND METHODS: The study retrospectively Analyzed 173 patients with laNPC treated with induction chemotherapy followed by concurrent chemoradiotherapy at Guangxi Medical University Cancer Hospital between January 2018 and October 2022. The cEBV-DNA levels and tumor volumes were measured. Spearman correlation analysis assessed the relationship between cEBV-DNA clearance time and tumor volume reduction. Group differences were evaluated using t-tests and analysis of variance. Survival outcomes were analyzed using Kaplan-Meier curves and Cox regression models, with statistical significance set at P < 0.05. RESULTS: Early clearance of cEBV-DNA was associated with significantly greater tumor volume reduction (nasopharynx: P = 0.024; left cervical lymph nodes: P = 0.002) and improved survival outcomes (overall survival: P = 0.026; progression-free survival: P = 0.016), though no difference was observed in the reduction of right cervical lymph nodes (P = 0.233). Chemotherapy toxicity did not differ between the early and non-early seronegative conversion groups (P > 0.05). Cox regression analysis revealed that smoking (P = 0.018), poor tumor response (P = 0.036), and lack of targeted therapy or immunotherapy (P = 0.043) were independent risk factors for worse overall survival. CONCLUSIONS: In pretreatment EBV-positive laNPC, early clearance of cEBV-DNA predicts better short-term tumor response and superior long-term survival, without exacerbating treatment-related toxicity. Furthermore, smoking, poor tumor response, and lack of targeted or immunotherapy independently correlate with worse prognosis.