For early gastric cancer, endoscopic resection and surgery are currently standard treatment options. Due to the complex lymphatic drainage of gastric cancer and the potential for skip metastasis—particularly with a significantly increased risk of lymph node involvement in pT1b tumors—laparoscopic and endoscopic cooperative surgery (LECS) has emerged as a novel approach that ensures oncological safety while preserving gastric function and improving quality of life. In LECS, the application of sentinel lymph node dissection for precise removal of perigastric lymph nodes has become a critical and essential step. Selecting appropriate tracers and using standardized injection techniques effectively enables visualization of sentinel lymph nodes. Moreover, en bloc resection of the sentinel lymph node basin is more oncologically sound than the “pickup” method, although it places higher demands on intraoperative frozen-section pathology. In the future, under the guidance of artificial intelligence-based models predicting lymph node metastasis, more precise sentinel lymph node dissection will likely represent an important direction for interdisciplinary collaboration between medicine and engineering.