关键词: 胃肠肿瘤, 纳米炭, 内镜定位, 淋巴结清扫, 围手术期管理

Abstract: Objective To establish a modified management protocol for endoscopic localization using submucosal nanocarbon injection, assess the interval from endoscopic localization with a nanocarbon tracer to surgery, and evaluate the association between the “three-stage, six-step” modified protocol and clinical indicators, to provide a reference for perioperative management of precise localization of gastrointestinal tumors. Methods A retrospective study was conducted among patients who underwent preoperative endoscopic localization by submucosal tracer injection at our digestive endoscopy center from October 2023 to April 2026. Patients were divided into three groups according to tracer type and management protocol： Group G1 （methylene blue with the conventional protocol, n=26）, Group G2 （nanocarbon with the conventional protocol, n=20）, and Group G3 （nanocarbon with the modified protocol, n=21）. The interval from endoscopic localization to surgery, operative duration, postoperative hospital stay, time to first flatus, time to enteral nutrition resumption, number of lymph nodes dissected, number of positive lymph nodes, and lymph node dissection adequacy rate （≥12 nodes for colorectal cancer, ≥16 nodes for gastric cancer） were compared among the three groups. Results Significant differences were observed among the three groups in the interval from endoscopic localization to surgery （P<0.001）, postoperative hospital stay （P=0.013）, number of lymph nodes dissected （P=0.008）, and lymph node dissection adequacy rate （P=0.045）, while no significant differences were found in operative duration, time to first flatus, or time to enteral nutrition resumption （all P>0.05）. Pairwise comparisons with Bonferroni correction showed that： under the same conventional management protocol （G1 vs. G2）, the nanocarbon group （G2） had a longer interval from endoscopic localization to surgery than the methylene blue group （G1） [median 22.29 （18.04, 27.27） h vs. 3.74 （3.15, 5.47） h, Z=-5.874,P<0.001]; with the same nanocarbon tracer （G2 vs. G3）, the modified management group （G3） had a shorter postoperative hospital stay than G2 [6.00 （6.00, 7.50） d vs. 8.00 （7.00, 9.00） d, Z=-2.869, P=0.012]; the lymph node dissection adequacy rate in G3 was 20.5 percentage points higher than that in G2 [90.5% （19/21） vs. 70.0% （14/20）, Yates′ corrected χ²=1.586, P=0.208]. Although the difference was not statistically significant after Yates′ correction, the magnitude of the increase suggested potential clinical relevance. Conclusion Nanocarbon tracer was associated with a longer observed interval from endoscopic localization to surgery compared with methylene blue, a finding consistent with the established evidence of its prolonged tissue retention. The “three-stage, six-step” modified management protocol was associated with a shorter postoperative hospital stay and showed a trend toward improved lymph node dissection quality. The protocol is well-structured and reproducible; however, its safety and long-term outcomes require further validation in prospective studies.

Key words: gastrointestinal tumors, nanocarbon, endoscopic localization, lymph node dissection, perioperative management