BACKGROUND The efficacy of endoscopic submucosal dissection (ESD) for undifferentiated early gastric cancer (UD EGC) is controversial due to the relatively high risk of lymph node metastasis. We compared long-term clinical outcomes of UD EGC between ESD and surgical resection groups.

METHODS We retrospectively reviewed the medical records of patients with UD EGC treated by either ESD or surgical resection between January 2007 and December 2014. Long-term clinical outcomes were compared between the two groups in terms of survival.

RESULTS A total of 1147 patients were enrolled with median follow-up duration of 59.1 months. ESD and surgical resections were performed in 126 and 1021 patients respectively. Additional surgery was performed in 22 patients after ESD. There were no significant differences in overall survival [total, p = 0.641; propensity score matching (PSM), p = 0.330; expanded criteria, p = 0.512]. Although the disease-free survival rate was lower in ESD group because of the higher rate of metachronous cancer development (total, p < 0.001; PSM, p = 0.001), the difference was not significant in the group within expanded criteria (p = 0.071).

CONCLUSIONS ESD could be a comparable treatment option with surgical resection for UD EGC within expanded criteria in terms of long-term survival. It is mandatory to establish a meticulous indication of ESD for UD EGC considering the risk of lymph node metastasis.