The value of integrating tumor volume and plasma Epstein-Barr virus DNA load during sequential chemoradiotherapy for prognostic prediction and therapeutic guidance in high-risk locoregionally advanced nasopharyngeal carcinoma

•Tumor volume is prognostic for locoregionally advanced nasopharyngeal carcinoma.•Epstein-Barr virus DNA loads during chemoradiotherapy is also a prognostic indicator.•A risk stratification system was developed incorporating these two factors.•The system improved survival prediction and clinical decision-making.