A New Approach to Ultra-Low Anterior Resection-Intersphincteric Dissection With Total Hiatal Ligament Excision for Very Low Rectal Cancer Located in the Posterior Wall of the Rectum: A More Satisfactory Technique for Local Recurrence Control.

Background: The hiatal ligament, as the anatomical landmark for the completion of total mesorectal excision (TME) for ultra-low rectal cancer, represents a continuation of the longitudinal muscle of the rectum. It receives vascular supply from the median sacral artery and contains lymphatic vessels. In cases where ultra-low rectal cancer is located in the posterior rectal wall, the hiatal ligament may theoretically serve as an anatomical region susceptible to direct tumor cell spread or distant metastasis.

Objective: To evaluate the effect of circumferential tumor location (CTL) on postoperative survival of low rectal cancer and to determine the effect of total hiatal ligament excision (THLE) on the prognosis of patients with posterior rectal cancer.

Methods: Patients with ultra-low rectal cancer who underwent laparoscopic surgery between March 2014 and October 2021 were enrolled in this study. Propensity score matching (PSM) analysis was used to compare the clinicopathological characteristics and prognosis of patients in the posterior group and the non-posterior group. Prognostic factors were identified using COX regression. PSM analysis was also used in the posterior tumor subgroup to compare the clinicopathological characteristics and prognosis of patients in the hiatal ligament traditional transection (HLTT) and THLE groups.

Results: After PSM, OS, and DFS were comparable between the posterior and non-posterior groups. Similarly, no difference was noted in the local recurrence rate between the two groups (p = 0.23). The prognosis of ultra-low rectal cancer was not affected by CTL. However, the local recurrence rate was significantly lower in the THLE group compared with the HLTT group (p = 0.023). Multivariate analysis of the posterior group identified CRM, TNM stage III, and HLTT as independent risk factors for local recurrence-free survival.

Conclusions: CTL is not a prognostic risk factor for low rectal cancer. In posterior wall tumors, THLE significantly reduces the local recurrence rate for low rectal cancer.