Purpose: To prove the feasibility of sentinel node navigation surgery (SNNS) in early gastric cancer patients with the risk of lymph node metastasis after endoscopic resection and preparation of multicenter phase 3 trial of stomach preserving surgery in these patients.

Contents: The number of enrollment is 247 patients. The patients underwent endoscopic resection for early gastric cancer, and the tumor was defined to be out of indication for endoscopic resection pathologically. So, additional gastrectomy is recommended for them.

The investigators will enroll patients who agree this study. After general anesthesia, Tc99m-Phytate with indocyanine green will be injected with endoscopy. Then sentinel basin will be detected using gamma probe and laparoscopic basin dissection will be done. Sentinel lymph node will be identify in back table dissection, and patients will undergo conventional gastrectomy. Detection rate and false negative rate will be evaluated by pathological review.

Sentinel basin dissection method

1. endoscopic tracer injection after general anesthesia
2. Tracer : Tc99m-phytate 3cc and indocyanine green 3cc mix --> Injection of the probe (1cc/site, 4 sites) around endoscopic submucosal dissection ulcer scar
3. Sentinel basin identification with laparoscopic probe
4. Dissection of the sentinel basin
5. Sentinel node dissection at back table
6. Conventional laparoscopic gastrectomy

Inclusion Criteria:

• No limitation for age if the patient is available for gastrectomy
• Patient who underwent endoscopic submucosal dissection and the tumor was defined as out of indication.

The expanded criteria for endoscopic resection are as follows

• criterion I: intramucosal tumor without ulcerative findings and of differentiated type with size > 2 cm
• criterion II: intramucosal tumor with ulcerative findings and of differentiated type with size ≤ 3 cm
• criterion III: intramucosal tumor without ulcerative findings and of undifferentiated type with size < 2 cm
• criterion IV, submucosal invasion < 500 mm and of differentiated type with size ≤ 3 cm)
• Eastern Cooperative Oncology Group (ECOG) performance scale 0 or 1

Exclusion Criteria:

• Inoperative due to severe cardiovascular or pulmonary disease
• Pregnant
• Patients who had previous gastric surgery
• Patients who had previous upper abdomen surgery except cholecystectomy, or radiation therapy on upper abdomen, or hypersensitivity to any medicine