Can CT Pelvimetry Be Used to Predict Circumferential Resection Margin Positivity in Laparoscopic Resection of Middle and Lower Rectum Cancer?

Background Previous studies have shown that pelvimetry can be valuable in predicting surgical difficulties in rectal cancer operations. However, its usability in predicting circumferential resection margin (CRM) involvement remains debatable. This study investigated the factors affecting CRM status and the importance of computed tomography (CT) pelvimetry in predicting CRM involvement in laparoscopic resection of middle and lower rectal cancer. Methodology In this study, we retrospectively investigated the data of 111 patients who underwent a laparoscopic operation for middle and lower rectum cancer at Ankara University Faculty of Medicine, Department of Surgical Oncology between January 2014 and January 2020. The predictive value of CT pelvimetry and other variables on the CRM status was analyzed. Results The following four pelvic parameters differed significantly between the genders: transverse diameter of the pelvic inlet (p = 0.024), anteroposterior diameter of the pelvic outlet (p = 0.003), transverse diameter of the pelvic outlet (p < 0.001), and pelvic depth (p < 0.001). The effect of pelvic anatomic parameters on CRM involvement was not found to be significant. It was found that tumor height from the anal verge (p = 0.004), tumor size (p < 0.001), and gender (p = 0.033) were significant risk factors for CRM involvement. Survival was poor in patients with male gender (p = 0.032), perineural invasion (p < 0.001), and grade 3 tumor. Conclusions In this study, no benefit was found in predicting CRM positivity from CT pelvimetry in the laparoscopic resection of middle and lower rectal cancer. Besides, tumor height from the anal verge, tumor size, and gender were important factors for CRM positivity. Although our study sheds light on this issue, prospective randomized studies with larger sample sizes are needed.