Clinical characteristics and prognostic value of pre‐retreatment plasma epstein‐barr virus DNA in locoregional recurrent nasopharyngeal carcinoma

PURPOSE: To define the clinical characteristics and prognostic value of pre‐retreatment plasma Epstein‐Barr virus (EBV) DNA, we investigated EBV status in locoregional recurrent nasopharyngeal carcinoma (lrNPC) patients. METHODS: Between April 2008 and August 2016, the data of patients with nonmetastatic lrNPC were retrospectively reviewed. The survival indexes of patients between different pre‐retreatment EBV status groups were compared. RESULTS: A total of 401 patients with nonmetastatic lrNPC were enrolled, and 197 (49.1%) patients had detectable pre‐retreatment plasma EBV DNA. Treatment included radiotherapy alone (n = 37 patients), surgery alone (n = 105), radiotherapy (n = 208), surgery combined with radiotherapy (n = 20), chemotherapy and targeted therapy (n = 31). Median follow‐up was 32 months. The 3‐year locoregional relapse‐free survival (LRRFS), distant metastasis‐free survival (DMFS), and overall survival (OS) rates for the entire cohort were 64.8%, 89.4%, and 58.8%, respectively. The estimated 3‐year LRRFS, DMFS, and OS rates for the pre EBV‐positive group vs the pre EBV‐negative group were 54.2% vs 75.0% (P < 0.001), 86.6% vs 91.9% (P = 0.05), 51.6% vs 65.9% (P = 0.01), respectively. Among patients in the clinical stage rI/II, there were 17 patients in the radiotherapy alone group and 49 patients in the surgery alone group. And there was no significant difference in overall survival between radiotherapy and surgery, even among the different pre‐EBV statuses (P > 0.05). In terms of long‐term toxic and side effects, the incidence of radioactive temporal lobe injury in the radiotherapy group was higher than that in the surgery group (35.3% vs 8.2%, P < 0.001), and no statistically significant difference was found in other long‐term toxic and side effects. CONCLUSIONS: The positive rate of pre‐retreatment plasma EBV DNA in lrNPC is lower than primary NPC. The prognosis of EBV DNA negative group is better than positive group. For locally early‐stage lrNPC, regardless of EBV DNA status, radiotherapy and surgery are available options and both can achieve better long‐term survival.