To analyze the influencing factors of the failure of NOSES for sigmoid cancer and rectal cancer.

A retrospective case-control study was conducted. Clinical data of 315 cases of sigmoid and rectal cancer patients undergoing trial NOSES in the colorectal surgery department of the First Affiliated Hospital of Zhengzhou University and Huaihe Hospital of He'nan University from January 2017 to March 2021, including preoperative examination, surgical process and surgical results. Univariate analysis and multivariate Logistic regression model were used to analyze the influencing factors leading to surgical difficulty.

Among the 315 patients included, 200 were males and 115 were females. The age was (61±13) years old, and the median size of the largest tumor was 3.6 (P25, P75: 2.8, 4.8) cm. Among them, 223 cases (70.8%) had difficulty in removing specimens by NOSES. Univariate analysis showed that BMI＞25.0 kg/m² (χ²=5.987, P=0.014), tumor obstruction (χ²=9.170, P=0.002), tumor distance from anal edge＞5.0 cm (χ²=5.275, P=0.022), tumor maximum diameter＞5.0 cm (χ²=5.735, P=0.017), the anterior and posterior diameter of the mesorectal＞6.0 cm (χ²=7.708, P=0.005), and the learning curve of the surgeon ≤50 cases (χ²=5.013, P=0.025) were associated with the difficulty of NOSES (all P＜0.05). Age, sex and history of abdominal surgery were not associated with the difficulty of NOSES (all P＞0.05). Multivariate analysis revealed that BMI＞25.0 kg/m², tumor obstruction, tumor distance from the anus to＞5.0 cm, tumor maximum diameter＞5.0 cm, mesorectal diameter＞6.0cm, and learning curve ≤50 cases were independent influencing factors for NOSES difficulty (all P＜0.05).

Preoperative evaluation of BMI, tumor distance from anal margin, tumor obstruction, tumor maximum diameter and mesorectal anteroposterior diameter is helpful for selecting suitable sigmoid colon and rectal cancer patients for NOSES.