Mesenteric Vascular Preconditioning Combined With Laparoscopic and Endoscopic Cooperative Surgery for Submucosal Tumor at the Gastroesophageal Junction

Inclusion Criteria: * Aged 18 to 80 (inclusive), of either gender. * Preoperative gastroscopy, enhanced CT, and/or endoscopic ultrasonography (EUS) examinations led to a clinical diagnosis of submucosal tumor (SMT) at the gastroesophageal junction. * The maximum diameter of SMT is 1\~5 cm (based on radiological measurements). * The distance from the upper margin of the SMT to the dentate line of the esophagogastric junction is ≤2 cm. * Eastern Cooperative Oncology Group (ECOG) physical status score of 0 or 1. * Plan to undergo laparoscopic surgery, and the researcher judges that the patient is suitable for the combined surgical procedure involved in this study. * Volunteer to participate in this study and sign a written informed consent form. Exclusion Criteria: * SMT that meets the absolute indications for endoscopic treatment alone (such as lesions with a diameter of \<1cm that can be completely resected endoscopically). * Patients with severe systemic diseases such as heart, lung, liver, and kidney dysfunction, who are unable to tolerate surgery or anesthesia after evaluation. * Women who are pregnant or breastfeeding. * Previous history of upper abdominal surgery. * Previously received upper abdominal radiotherapy. * Have suffered from or currently suffer from other malignant tumors within the past 5 years. * Lesions accompanied by clear ulcers, metastasis, or lesions after neoadjuvant and conversion therapy. * The researcher determines that there are any other situati…