Relationship between HER2 overexpression and long-term outcomes of early gastric cancer: a prospective observational study with a 6-year follow-up

BACKGROUND: Studies have confirmed the prognostic value of the expression status of human epidermal growth factor receptor 2 (HER2) in advanced gastric cancer. However, its role in early gastric cancer (EGC) remains largely unknown. This study explored the association between HER2 overexpression and clinical outcomes of patients with EGC. METHODS: A total of 211 patients who had undergone endoscopic treatment for pN0 EGC were enrolled. The HER2 expression status was assessed using immunohistochemistry (IHC). RESULTS: The prevalence of HER2 overexpression was 14.2%. HER2 overexpression showed a significant correlation with tumor location (P = 0.033). Multivariate analysis showed that HER2 overexpression was significantly associated with an increased risk of tumor recurrence in pN0 EGC (hazard ratio [HR] = 3.97; 95% confidence interval [CI] 1.30–12.14; P = 0.016) but not overall survival (OS) or disease-specific survival (DSS). Of the included patients, age was associated with OS (HR = 1.11; 95% CI 1.04–1.18; P = 0.002], whereas lymphovascular invasion was significantly associated with poor DSS (HR = 33.66; 95% CI 3.05–371.25; P = 0.004). CONCLUSION: This study shows that HER2 overexpression is significantly associated with tumor recurrence in pN0 EGC. Hence, Her2 testing at diagnosis is important and differential treatment and/or follow up strategies for patients with Her2 overexpression may merit future study. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12876-022-02309-7.