Gastric cancer is a common malignant tumour worldwide, and in China, the incidence and mortality rates of gastric cancer remain high. Standardised surgical treatment is effective, but the normal structure of the stomach undergoes irreversible changes, leading to a series of adverse reactions. At the same time, some early-stage gastric cancer patients cannot have the lesions completely removed endoscopically, and conventional surgery can affect postoperative normal life. Therefore, laparoscopic and endoscopic cooperative surgery has become a focus for precise stomach-preserving surgery. Participants meeting the surgical criteria are selected, and after discussing the treatment plan with their families and signing informed consent forms, relevant examinations are completed. During surgery, lesions are explored together using laparoscopy and endoscopy, then a fluorescent tracer is injected around the lesion and the lesion boundary is marked. Fifteen minutes after injecting the fluorescent tracer, the illuminated perigastric lymph nodes are the sentinel lymph node region (SLNB), and all fluorescent lymph nodes (sentinel lymph nodes) are removed and sent for intraoperative frozen pathology. If the SLNB is negative: a dual-endoscope combined local gastric resection (endoscope combined with laparoscopic local gastric resection or a modified procedure) is performed to completely remove the lesion, ensuring a negative margin. If the SLNB is positive: immediate conversion to laparoscopic-assisted radical gastrectomy (D2 lymph node dissection) is carried out. For SLNB-negative cases, the dual-endoscope combined local gastric resection specimen is placed in a retrieval bag for full removal and examination, with the stomach wall incision then closed by suturing or using a stapler. Postoperative follow-up includes monitoring tumour outcomes and quality of life.