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.