Monitoring tumor recurrence with nasopharyngeal swab and latent membrane protein-1 and Epstein-Barr nuclear antigen-1 gene detection in treated patients with nasopharyngeal carcinoma

Objectives: Epstein-Barr virus (EBV) is closely related to nasopharyngeal carcinoma (NPC). Detection of EBV genomic DNA in a nasopharyngeal swab specimen may indicate the presence of NPC, and the EBV genomic DNA is only detected in patients with NPC and not in other head and neck cancers. This study aims to prove that detection of EBV genomic DNA by means of the latent membrane protein (IMP)-1 gene and the Epstein-Barr nuclear antigen (EBNA)-1 gene in the nasopharynx in NPC patients after radiation therapy indicates local recurrence of NPC. Study Design: Prospective. Methods: Nasopharyngeal swab with polymerase chain reaction (PCR)-based LRIP-1 and EBNA-1 gene detection was used to monitor local recurrence in 84 NPC patients who completed radiation therapy. Results: Of the 12 patients demonstrating positive IMP-1 and EBNA-1 gene, 11 had local recurrence, and 10 of them had early rT₁ mucosal recurrence. Subsequent salvage nasopharyngectomy controlled local disease in nine. Only one local recurrence in the skull base failed to show LMP-1 gene initially. Detection of LMP-1 gene and later verification with EBNA-1 gene from nasopharyngeal swabs in NPC patients after radiation therapy predicted local recurrence with a sensitivity of 91.7% and a specificity of 98.6%. Conclusions: Nasopharyngeal swab with LMP-1 and EBNA-1 gene detection is a useful and reliable method to monitor local recurrence in NPC patients. It helps to detect recurrence early and may improve local control and enhance survival.