• Men and women aged 19-70 years who underwent endoscopic resection for high-grade adenoma or early gastric cancer (category 4 \[non-invasive high grade neoplasm\] or category 5 \[invasive neoplasia\] according to the Vienna classification of gastrointestinal epithelial neoplasia \[Schlemper RJ, et al. Gut 2000;47:251-255.\])

• Final pathological results after endoscopic resection met the absolute or expanded criteria according to the Japanese Gastric Cancer Treatment guideline 2014 (version 4)

• Patients who had negative H. pylori status or those who eradicated H. pylori status

• Willingness to sign an informed consent form