Based on a comprehensive molecular characterization of gastric cancer, Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) can be classified as one of the four subtypes of gastric cancer (GC). Several studies have shown significantly better prognosis of EBVaGC compared with EBV-negative GC (EBVnGC). However, no published study has yet investigated the clinical significance of standard adjuvant chemotherapy in patients with resected EBVaGC. Accordingly, the present study analyzed the prognostic differences between EBVaGC and EBVnGC, and their survival impacts on standard adjuvant chemotherapy.
This study retrospectively reviewed 773 patients with gastric cancer who underwent surgical resection at Kyungpook National University Chilgok Hospital, between January 2011 and December 2017. The patients were enrolled according to the following criteria: 1) pathologically diagnosed with primary gastric adenocarcinoma, 2) the presence of test using EBV-encoded RNA in situ hybridization, 3) stage II/III according to the seventh edition of the UICC/AJCC for the stomach, and 4) postoperative adjuvant chemotherapy.
Among 276 eligible patients, 59 (21.4%) and 217 patients (78.6%) were determined as EBVaGC and EBVnGC, respectively. One hundred twenty-nine (46.7%) patients were classified as stage II and 147 (53.3%) were as stage III. As for adjuvant chemotherapy, 87 patients (31.5%) received capecitabine and oxaliplatin (XELOX), while 189 (68.5%) received S-1, respectively. With a median follow-up duration of 21.3 months (2.4-89.0), the estimated 3-year disease-free survival (DFS) and overall survival (OS) rates were 74.8% and 83.0%, respectively. In a univariate analysis and multivariate analysis using a Cox proportional hazard model, EBV-positivity was not significantly associated with disease-free survival (p = 0.630) for all patients and XELOX or S-1 group.
In conclusion, EBV-positivity was not found to be associated with prognosis in patients with curatively respective gastric cancer who received standard adjuvant chemotherapy. Accordingly, the standard adjuvant chemotherapy can be used for patients with EBVaGC.
Clinical trial identification
Legal entity responsible for the study
Jong Gwang Kim.
Has not received any funding.
All authors have declared no conflicts of interest.