The value of nasopharyngeal brush versus plasma <scp>EBV DNA</scp> detection in diagnosing local recurrence of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) remains a major challenge due to the high incidence of recurrence, often leading to therapeutic failure. Early detection of recurrence is critical, yet effective surveillance methods are limited. This study aims to evaluate the utility of Epstein-Barr virus (EBV) DNA detection in nasopharyngeal brush samples for identifying recurrent NPC. A total of 187 NPC patients who had undergone radical radiotherapy with or without chemotherapy were included. EBV DNA levels in both nasopharyngeal brush and plasma samples were analyzed using real-time quantitative PCR. Head and neck MRI, sinus endoscopy examination, and biopsy of suspicious lesions were used as the gold standard to confirm recurrence. Patients without recurrence after more than 1 year of follow-up served as controls. Nasopharyngeal brush EBV DNA detection demonstrated significantly higher sensitivity (95.7%) for detecting recurrence compared to plasma EBV DNA testing (61.4%), with comparable specificity (94.0% vs. 96.6%). The positive predictive value was similar between methods, whereas the negative predictive value was markedly higher for the nasopharyngeal brush group (97.3% vs. 80.7%). These findings suggest that EBV DNA detection in nasopharyngeal brush samples is a highly sensitive and minimally invasive supplementary tool for monitoring NPC recurrence. This approach offers superior sensitivity and an improved negative predictive value compared to plasma EBV DNA testing, and may enhance early surveillance and clinical management of NPC recurrence.