To investigate the clinical effect of laparoscopic transsphincterectomy (ISR) with different distal incisional margins after neoadjuvant therapy for locally advanced rectal cancer (LARC), and to analyze the influence of surgical distance on the prognosis of patients with different pathological TNM stages (ypTNM).

The clinical data of 86 LARC patients who received neoadjuvant therapy from January 2019 to December 2021 were retrospectively analyzed. All patients underwent laparoscopic ISR surgery after neoadjuvant therapy. According to the distance of distal incisal margin during operation, the patients were divided into the group <1 cm (n=38 cases) and the group ≥1 cm (n=48 cases). Statistical software SPSS 23.0 was used to analyze the data. Perioperative indexes, anal function and quality of life of different surgical resection margin groups were represented by (). Independent sample t test was used for comparison between groups. Postoperative complications were represented by [cases (%)], and Fisher exact probability or χ² test was used for comparison between groups. Kaplan-Meier method was used to analyze the relationship between surgical resection margin distance and disease-free survival (DFS) and overall survival (OS) of patients in different pathological stage subgroups, and the survival difference was tested by Log-Rank. P<0.05 was considered statistically significant.

There were no significant differences in perioperative parameters, postoperative complications, anal function, quality of life and OS survival between the two groups (P>0.05). The postoperative local recurrence rate and cumulative DFS survival in patients with distal resection margin ≥1 cm were better than those in <1 cm group (P<0.05). The postoperative DFS survival of ypT₁ and ypT₂ patients was not correlated with the distance of distal incisal margin (P>0.05). DFS survival in patients with distal resection margin <1 cm at ypT₃ stage was lower than that in patients with distal resection margin ≥1 cm (P<0.05).

After neoadjuvant treatment for locally advanced rectal cancer, the selection of ISR resection margin did not affect perioperative results, the occurrence of complications, postoperative anal function recovery and quality of life. The distance of distal resection margin <1 cm is associated with postoperative local recurrence and DFS survival, especially in ypT₃ patients.