Abstract:Abstract: Objective?To investigate the role of preoperative endoscopic nano-carbon labeling in the localization of the lesions, lymph node tracing and postoperative lymph node sorting in gastrointestinal cancer surgery.?Methods?From February 2018 to May 2019, 50 cases of gastric cancer and 44 cases of colorectal cancer were treated with preoperative nano-carbon labeling and the conditions of endoscopic labeling, intraoperative and postoperative conditions of the selected cases were summarized and analyzed.?Results?All the patients underwent endoscopic nano-carbon labeling at one time completed before surgery. The endoscopic operation time was about 5.0?~?15.0 min, and no bleeding, perforation or other complications occurred. The labeling time ranged from 3?h?~?5?d before surgery. 38 patients with laparoscopic surgery, 56 patients underwent open operation, intraoperative localization tumors had time 0.5?~?2.5 min, operation time 60.0?~?135.0 min. During the operation, the positioning sites of nano-carbon were all clearly visible, required for cleaning of regional lymph nodes are very visible and in black dye. The lymph nodes of postoperative samples were collected by nano carbon imaging combined with arterial approach, the average working time about 15.0 min, 50 patients with gastric cancer were sorting through lymph node number average 43, 44 patients with colorectal cancer were sorting through lymph node number average 29 (All above are higher than the NCCN guidelines).?Conclusion?The preoperative endoscopic nano-carbon labeling of gastric cancer and colorectal cancer is helpful for the accurate localization of the lesions, especially the small lesions or the lesions not invading the digestive tract serous layer. Preoperative markers can fully diffuse the carbon nanoparticles, facilitate intraoperative dissection, facilitate lymph node sorting of surgical specimens, and obtain more lymph nodes, which is conducive to pathological staging and postoperative adjuvant treatment.