Pathological features and risk factors for submucosal infiltration of colorectal lateral spreading tumors.

Background: To observe the endoscopic and pathological characteristics of laterally spreading tumors (LSTs) and explore the risk factors for carcinogenesis and submucosal infiltration.

Aim: To analyze the clinicopathological features of colorectal LSTs treated endoscopically and determine risk factors associated with carcinogenesis and submucosal invasion, providing evidence-based guidance for optimal treatment strategy selection.

Methods: This study retrospectively analyzed the sex, age, and endoscopic and pathological features of patients who underwent endoscopic treatment for colorectal LSTs in our hospital from January 2021 to July 2024. Single-factor analysis was used to identify the risk factors for cancer and submucosal infiltration, and the factors with statistical significance were included in multivariate logistic regression analysis.

Results: A total of 422 patients, including 224 males and 198 females, aged 63.45 ± 9.23 years, were included. There were 456 LST lesions in total. The length of the endoscopically resected specimens was 3.01 ± 0.48 cm, and the length of the lesions was 2.37 ± 1.59 cm. It was located in 115 rectums (25.2%), 40 sigmoid colon (8.8%), 26 descending colon (5.7%), 109 transverse colon (23.9%), 112 ascending colon (24.6%), and 54 ileocecal regions (11.8%). Endoscopic submucosal dissection (ESD) was performed in 237 patients (52.0%), and endoscopic mucosal resection (EMR) was performed in 95 patients (20.8%). There were 113 EMR with precutting cases (24.8%), 11 ESD with snare cases (2.4%), 4 delayed bleeding cases and 5 intraoperative perforations. The pathological results revealed 119 cases of low-grade intraepithelial neoplasia (26.1%), 221 cases of high-grade intraepithelial neoplasia (48.5%), 82 cases of intramucosal carcinoma (18.0%), and 34 cases of submucous invasive carcinoma (7.5%). Multiple logistic regression analyses revealed that lesion size ( > 2 cm), lesion location (rectal) and endoscopic classification [false depressed tubulovillous adenoma (LST-NG pseudodepressed type, LST-NG-PD), type 1 particles (LST-G homogenous type), and LST-G nodular mixed type], accompanied by large nodules (with) were independent risk factors for carcinogenesis; endoscopic classification (LST-NG-PD) and the presence of large nodules were independent risk factors for submucosal infiltration.

Conclusion: These risk factors provide practical guidance for treatment selection: LST-NG-PD with large nodules should prioritize ESD, while high-risk rectal lesions > 2 cm may require additional imaging evaluation before endoscopic resection.