Factors Influencing Pathologic Results after Total Mesorectal Excision for Rectal Cancer: Analysis of Consecutive 100 Cases

Background The aim of this study was to analyze clinical and anatomical factors affecting the pathologic quality of the resected specimen after total mesorectal excision (TME) for rectal cancer. Methods A total of 100 patients who underwent TME for mid or low rectal cancer were evaluated prospectively. MRI pelvimetry data (transverse diameter, obstetric conjugate, interspinous distance, sacrum length, and sacrum depth) were analyzed as anatomically affecting factors to postoperative specimen quality. Sex, body mass index (BMI), type of surgery, tumor size, and tumor distance from the anal verge were analyzed as clinically affecting factors. The gross judgment of resected specimen, circumferential resection margin and the number of harvested lymph nodes were used to access postoperative specimen quality. Results The univariate and multivariate analysis showed that narrow obstetric conjugate and shorter interspinous distance were related to the inadequate quality of the mesorectum in the specimen (P = 0.022, P = 0.030). Interspinous distance was a predicting factor of a positive circumferential resection margin (P = 0.007). There were no clinical factors affecting the inadequate quality of the mesorectum or positive circumferential resection margin. Moreover, there were no clinico-anatomical factors affecting the number of harvested lymph nodes after TME. Conclusion Narrow obstetric conjugate and shorter interspinous distance were factors leading to poor postoperative specimen quality. Rectal cancer patients with narrow obstetric conjugate or shorter interspinous distance should be considered as high-risk patients with regard to specimen quality, which is in turn related to oncological outcome.