To explore the risk factors and remedial measures for failure of anal preservation caused by inadequate distal resection margin in laparoscopic surgery for low rectal cancer.

A retrospective analysis was performed on 203 patients who were diagnosed as having low rectal cancer (preoperatively staged as T₁-4aN₀-2M₀) at our center from October 2017 to June 2019 and underwent laparoscopic rectal cancer surgery. Among the patients included, 165 underwent laparoscopic Dixon surgery for low rectal cancer (Dixon group) and 38 underwent salvage intersphincteric anal sphincteric resection (sISR group) due to distal resection margin (DRM) <1 cm, which resulted in the failure of anus function preservation. Using the chi-square test and multivariate regression analysis, the association of gender, body mass index (BMI), tumor distance to the anus, tumor size, tumor center location, mesorectal fat area (MFA), and intertubercle distance (IT) with DRM＜1 cm was statistically analyzed to identify the risk factors for failure of anal preservation. Duration of hospitalization, hospitalization cost, and the incidence of complications were compared between the two groups. Wexner score was used to compare the anal function of the two groups after stoma closure. The metastasis rate and recurrence rate at 2 years after operation were compared between the two groups.

BMI, IT, MFA, distance between tumor and anal margin, and location of tumor center were significantly associated with DRM＜1 cm (P＜0.05). There was no significant difference in average length of hospitalization, average hospitalization cost, or the incidence of postoperative complications between the two groups (P＜0.05). Wexner score was used to evaluate the anal function after stoma closure, and there was no statistical difference between the two groups (P＞0.05). There was no statistical difference in 2-year metastasis rate or recurrence rate between the two groups (χ²=0.772, P=0.084).

BMI, IT, MFA, tumor distance to anal margin, and tumor center location in low rectal cancer patients may lead to DRM＜1 cm resulting in the failure of anal preservation in laparoscopic Dixon surgery for low rectal cancer, and sISR can preserve the anal function of patients again, without increasing the average length of hospital stay, hospitalization costs, postoperative complications, and the disease 2-year recurrence rate and metastasis rate after surgery.