Prospective evaluation of colorectal cancer resection margins: Intraoperative, early postoperative and pathological measurements.

Abstract

Accurate assessment of resection margins is important in colorectal cancer surgery, as margin distance may influence pathological staging and subsequent therapeutic decisions. This study aimed to evaluate differences between intraoperative measurement, immediate postoperative measurement, and pathological measurement after formalin fixation of the longitudinal margin closest to the tumour. A prospective observational single-centre study was conducted including consecutive patients undergoing elective colorectal resection for colon or upper rectal cancer between August 2024 and July 2025. The distance between the tumour edge and the closest longitudinal margin was measured at three time points: intraoperatively before colonic transection, 15 min after resection on the surgical specimen, and in the pathological report after fixation in 10% formalin. Continuous variables were expressed as mean and standard deviation. Comparisons between measurements were performed using the paired Student's t-test. Twenty-five colectomies for colorectal cancer were performed during the study period, of which 17 patients were included in the analysis. Eight cases were excluded due to the inability to measure the specimen at the predefined time points. A significant reduction in margin length was observed between intraoperative measurement and measurement performed 15 min after resection (p < 0.001). The pathological margin reported after formalin fixation was also significantly shorter than the intraoperative measurement (p < 0.001). The mean intraoperative margin was 10 cm, decreasing to 7.7 cm at 15 min after resection and to 5.1 cm after formalin fixation. Significant differences exist between intraoperative margin measurement, immediate postoperative measurement, and pathological measurement after formalin fixation in colorectal cancer surgery. These findings highlight the importance of interdisciplinary communication between surgeons, pathologists, and oncologists to optimise therapeutic decision-making.