Lymph node metastases in early gastric cancer: Japanese Gastric Cancer Treatment Guidelines can be used for endoscopic resection in the West.

Background and study aims: The eCura system has been shown to accurately delineate early gastric cancers with negligible risk of lymph node metastases, which, therefore, would be considered endoscopically cured. However, this classification was based predominantly on data from high-incidence Eastern countries. We sought to assess whether these criteria can be safely applied in a Western population. Patients and methods: Data were retrospectively recorded for patients who underwent gastrectomy in four Australian tertiary centee over two decades. Demographic data, lesion characteristics (size, differentiation, invasion depth, lymphovascular invasion, and ulceration) as well as number of lymph node metastases was recorded. Patients given neoadjuvant chemotherapy were excluded. Results: A total of 1,465 gastrectomy specimens were reviewed, including in 558 patients who underwent resection of gastric adenocarcinoma without neoadjuvant chemotherapy (mean age 67.9, 64.2% male). Of these, 101 (18.1%, confidence interval [CI] 15.4%-21.9%) had T1 disease (T1a = 30, T1b = 71). Of the lesions, 11.5% (n = 64, CI 9.1%-14.4%) met the 2021 Japanese "absolute criteria" for endoscopic resection, with 7.8% of these (n = 5, CI 3.4%-17%) having positive lymph nodes at gastrectomy. Of them, 9.9% (n = 55, CI 7.6%-12.6%) would have been considered eCura A or B, with none of these having positive lymph nodes at gastrectomy. Conclusions: The eCura system for defining endoscopic curability could have been safely applied in this Western population. Even in Western countries, patients with early gastric cancer that meets Japanese guidelines for endoscopic resection should, where possible, undergo en bloc endoscopic submucosal dissection. Lesions classified histologically as eCuraA or B should be considered endoscopically cured.