Differentiation of recurrent nasopharyngeal carcinoma and skull base osteoradionecrosis by Epstein-Barr virus-derived latent membrane protein-1 gene.

OBJECTIVES: In patients with nasopharyngeal carcinoma (NPC), the differentiation between recurrent primary cancer and osteoradionecrosis (ORN) is clinically difficult. Epstein-Barr virus (EBV)-derived latent membrane protein-1 (LMP-1) has been demonstrated to be highly associated with NPC. The objective of this study is to define the role of the LMP-1 gene in the differential diagnosis of recurrent NPC and ORN.

STUDY DESIGN: Prospective.

METHODS: From July 1998 to June 2000, 15 postirradiated patients with NPC who were initially diagnosed to have skull base ORN underwent endoscopic sequestrectomy. The sequestra were examined for the presence of the LMP-1 gene and cancer.

RESULTS: Two of 15 patients had recurrent cancer and only these two patients demonstrated a positive LMP-1 gene in their surgically removed sequestra. The presence of the LMP-1 gene in the sequestrum coincided with biopsy-proven local recurrence.

CONCLUSIONS: The LMP-1 gene is a potential marker to differentiate between recurrent NPC and ORN. The presence of the LMP-1 gene in patients with ORN may indicate local recurrence.