Demographic/clinicopathological characteristics and prognosis of resectable Epstein-Barr virus-associated gastric cancer: a nested case-control study from an Eastern China

Background: Epstein-Barr virus-associated gastric cancer (EBVaGC) represents a distinct molecular subtype of gastric cancer (GC). This multicenter study aimed to investigate the clinicopathological characteristics and prognosis of resectable EBVaGC patients. Methods: Data were prospectively collected and retrospectively analyzed from 1,400 patients at Ningbo No. 2 Hospital from January 2014 to December 2023 and 55 EBVaGC patients were identified. Additionally, 95 EBVaGC patients from two external cooperative centers were included. A 1:4 propensity score matching (PSM) analysis was performed between EBVaGC patients and EBV-negative gastric cancer (EBVnGC) patients. Median follow-up duration was 34 months. Results: Among the 150 EBVaGC patients, the median age was 64, and 88.7% were male. Undifferentiated tumors were more common. During the follow-up, 121 EBVaGC patients did not experience recurrence. After PSM, there were 137 EBVaGC patients and 548 EBVnGC patients. In EBVaGC patients, elevated Carcinoembryonic Antigen (CEA) levels (HR = 8.11, p=0.025) and pathological tumor-node-metastasis (pTNM) stage III (HR = 19.57, p=0.008) were independent risk factors for overall survival (OS). For disease-free survival (DFS), elevated CEA levels (HR = 6.23, p=0.035) and pTNM stage III (HR = 18.51, p=0.007) were independent risk factors. There was no significant difference in OS between the two groups (p=0.204). Compared to EBVnGC patients, EBVaGC patients showed a trend towards better DFS, although this did not reach statistical significance(p=0.061). Conclusion: EBVaGC patients exhibit unique clinicopathological characteristics and may show a trend toward better prognosis compared with EBVnGC patients, although this difference did not reach statistical significance.