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

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. 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. 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. 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.