Prognostic efficacy of combining tumor volume with Epstein-Barr virus DNA in patients treated with intensity-modulated radiotherapy for nasopharyngeal carcinoma

Abstract Objectives To evaluate the prognostic effect of combining tumor volume with pre-treatment plasma Epstein-Barr virus DNA (EBV DNA) in patients treated with intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). Materials and methods A total of 180 consecutive NPC patients enrolled in this observational, prospective study and underwent IMRT. Tumor volume was delineated with IMRT planning system and plasma EBV DNA level was quantified by polymerized chain-reaction assay. The effects of tumor volume and EBV DNA level, either alone or in combination, on 5-year overall survival (OS) were cross-compared. Results The 5-year OS in patients with gross tumor volume of nasopharynx (GTVnx) ⩽ 20 cc and >20 cc was significantly different ( P  = 0.001). The 5-year OS in patients with EBV DNA P Conclusion Combining tumor volume with pre-treatment plasma EBV DNA level altered survival-risk definition for subgroups of NPC patients and this combination, more than individual factors alone, improved the accuracy of prognostic evaluation.