Intersphincteric resection for low-lying rectal cancer: analysis of risk factors and establishment of a preoperative assessment system for postoperative anal function.

Purpose: In recent years, intersphincteric resection has increasingly become a viable alternative to abdominoperineal resection due to its significant preservation of the anus. Previous studies have indicated that intersphincteric resection has provides comparable oncological outcomes to APR, but anal incontinence remains a common postoperative complication. we reassessed identify preoperatively controllable and measurable risk factors that may affect anal function following intersphincteric resection, and to attempt to construct a preoperative risk assessment system for anal function after intersphincteric resection, thereby standardizing intersphincteric resection treatment for low rectal cancer.

Materials and methods: This single-center retrospective study included 51 patients who underwent intersphincteric resection surgery between January 2018 and March 2023 and maintained autonomous defecation for one year or more were selected. Using Independent samples t-test, rank-sum test, Fisher's exact test, and linear regression, we analyzed anal function at 12 months postoperatively and the clinical factors influencing it. Construction of a postoperative fecal incontinence risk assessment scale for ISR based on standardized coefficients in multifactorial linear regression.

Results: Age, clinical T stage, preoperative puborectalis muscle thickness, and preoperative chemoradiotherapy were identified as independent factors affecting postoperative anal function.

Conclusions: Older age, higher clinical T stage, thinner preoperative puborectalis muscle thickness, and preoperative chemoradiotherapy are associated with poorer postoperative anal function. Patients with 0-1 high-risk factors can be recommended for intersphincteric resection treatment; those with 3 high-risk factors should not undergo intersphincteric resection; and patients with 2 high-risk factors should have a thorough discussion regarding the potential risks before a cautious surgical decision is made.