Endoscopic Carbon Nanoparticles Labeling Technique Assisted in situ Resection After Neoadjuvant Chemoradiotherapy for Rectal Cancer:Clinical Analysis of 46 Cases / 中国微创外科杂志

ABSTRACT

Objective To investigate the value of endoscopic carbon nanoparticles labeling technique assisted in situ resection after neoadjuvant chemoradiotherapy(nCRT)for middle and low locally advanced rectal cancer(LARC).Methods From January 2020 to January 2023,46 cases of middle or low LARC were selected for endoscopic injection of carbon nanoparticles suspension to label the lower edge of the tumor before nCRT,and laparoscopic anterior resection of the rectum was performed after nCRT.The main observations were the visualization of carbon nanoparticles marker during the operation,the length of each area(primary tumor area,tumor regression scar,distal resection margin,and regression area of lower edge of tumor)of surgical specimens and the positive rate of distal resection margins.Results The median interval between injection of carbon nanoparticles suspension and surgery was 105(77-182)d in the46 cases.Carbon nanoparticles remnants were observed on the rectal mucosal surface in all the patients after nCRT by endoscopy.During laparoscopic anterior rectal resection surgeries,carbon nanoparticles marker exposure on the surface of the rectal intrinsic fascia observed in 41 cases(89.1%),of which38 cases were judged as good exposure(the width of marker area≤1.5 cm,which assisted the operator accurately determining the distal surgical margins)and 3 cases were judged as inferior exposure(a larger range of black staining whereas in situ resection of the tumor still achievable).In another 5 cases,the carbon nanoparticles marker could not be observed and were judged as exposure failure.Intraoperative cryopathology showed that all distal resection margins were negative.Measurement of 30 surgical specimens with identifiable primary tumor area showed that the length of resected intestinal canal was 17.9(10.1-25.7)cm,the diameter of primary tumor area was(4.3±0.8)cm,the diameter of scar after tumor regression was 2.5(0.8-4.8)cm,and the length of regression of tumor lower margin was 1.0(0-2.9)cm.The length of distal resection margins in middle rectal cancer(n =17)was3.4(1.5-4.3)cm and in low rectal cancer(n =13)was1.6(0.5-2.8)cm.Conclusion Application of carbon nanoparticles labeling technology before nCRT for rectal cancer can effectively mark the lower margin of the primary tumor in a long time and assist surgeons to precisely remove the primary tumor area.