Recently, laparoscopic gastrectomy has been gradually accepted by surgeons worldwide for gastric cancer treatment. Complete dissection of the lymph nodes and the establishment of the surgical margin are the most important considerations for curative gastric cancer surgery. Previous studies have demonstrated that indocyanine green (ICG)-traced laparoscopic gastrectomy significantly improves the completeness of lymph node dissection. However, it remains difficult to identify the tumor location intraoperatively for gastric cancers that are staged ≤T3. Here, the investigatorsinvestigated the feasibility of ICG fluorescence for lymph node mapping and tumor localization during totally laparoscopic distal gastrectomy.Preoperative and perioperative data from consecutive patients with gastric cancer who underwent a laparoscopic proximal gastrectomy were collected and analyzed. The investigators want to know if near-infrared fluorescence imaging with ICG can be successfully used in laparoscopic proximal gastrectomy, and if it contributes to both the completeness of D2 lymph node dissection and confirmation of the gastric transection line. The application of ICG labeled near infrared imaging fluorescence laparoscopic technology is still in the stage of exploration and experience accumulation, and it needs to be comprehensively evaluated through a large number of prospective randomized controlled studies.

Recently, laparoscopic gastrectomy has been gradually accepted by surgeons worldwide for gastric cancer treatment. Complete dissection of the lymph nodes and the establishment of the surgical margin are the most important considerations for curative gastric cancer surgery. Previous studies have demonstrated that indocyanine green (ICG)-traced laparoscopic gastrectomy significantly improves the completeness of lymph node dissection. However, it remains difficult to identify the tumor location intraoperatively for gastric cancers that are staged ≤T3. Here, the investigatorsinvestigated the feasibility of ICG fluorescence for lymph node mapping and tumor localization during totally laparoscopic distal gastrectomy.Preoperative and perioperative data from consecutive patients with gastric cancer who underwent a laparoscopic proximal gastrectomy were collected and analyzed. The investigators want to know if near-infrared fluorescence imaging with ICG can be successfully used in laparoscopic proximal gastrectomy, and if it contributes to both the completeness of D2 lymph node dissection and confirmation of the gastric transection line. The application of ICG labeled near infrared imaging fluorescence laparoscopic technology is still in the stage of exploration and experience accumulation, and it needs to be comprehensively evaluated through a large number of prospective randomized controlled studies.By recruiting patients and signing informed consent, randomized control was used to divide patients into the experimental group (fluorescently labeled fluorescently laparoscopic proximal gastric cancer surgery) and the control group (fluorescently labeled fluorescently laparoscopic proximal gastric cancer surgery). In the experimental group, indocyanine green fluorescence labeling was performed under gastroscope before surgery and internal jugular vein puncture was performed routinely for better fluid replenishment after surgery. Lymph nodes and diseased stomach tissues were collected during operation. Postoperative assessment was made for ICU support, routine acid-suppressing therapy, prophylactic antibiotics, analgesia, and nausea suppression. The patients were followed up for 3 years. The primary outcome was 3-year disease-free survival, and the secondary outcome was lymph node positive rate, early complication rate and surgical mortality. The investigators plan to obtain more precise evidence-based medical evidence through this project.

Inclusion Criteria:

1. 18 years old < age < 75 years old
2. The primary gastric lesion was pathologically diagnosed as proximal gastric adenocarcinoma by endoscopic biopsy (papillary adenocarcinoma PAP, tubular adenocarcinoma TUB, mucinous adenocarcinoma MUC, signed-ring cell carcinoma SIG, poorly differentiated adenocarcinoma POR)
3. Preoperative clinical staging was CT1-4A, N-/+, and M0, according to AJCC-8th TNM tumor staging
4. No distant metastasis was found in preoperative examination, and the tumor did not directly invade pancreas, spleen or other adjacent organs
5. ECOG physical status score 0/1 before surgery Preoperative ASA score I-III

(7) Informed consent of patients

Exclusion Criteria:

1. Suffering from severe mental illness
2. Severe complications cannot tolerate surgery
3. Simultaneous surgical treatment of other diseases is required
4. History of gastric surgery (including ESD/EMR for gastric cancer)
5. Tumors involving esophagus or duodenum were confirmed preoperatively
6. Neoadjuvant therapy has been implemented
7. Leather stomach
8. Refusing laparoscopic surgery