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Objective: We aimed to investigate the clinical outcomes of endoscopic submucosal dissection (ESD) for the treatment of colorectal laterally spreading tumors (LSTs) and the factors related to technical difficulty. Methods: Consecutive patients who underwent ESD for colorectal LSTs between June 2013 and January 2019 were retrospectively included. Factors associated with difficult ESD procedures (defined as conversion to piecemeal resection or discontinuation of endoscopic procedure), and dissection with a slow speed (<8 mm2/min), were determined using the logistic regression analysis. Results: A total of 325 patients with 342 colorectal LSTs (median size 20.0 mm) were enrolled. The proportions of granular (LST‐G) and non‐granular LST (LST‐NG) were 62.9% and 37.1%, respectively. The overall en bloc and complete resection rates were 89.8% and 81.9%, respectively. The endoscopic procedure was discontinued in four lesions (1.2%), and 31 (9.1%) converted to piecemeal resection because of technical difficulty. Using multivariate analysis, positive non‐lifting sign (odds ratio [OR] 19.9, P < 0.001), tumor size ≥20 mm (OR 10.0, P < 0.001), and less experienced endoscopists (OR 3.7, P = 0.005) were independent factors for technically difficult procedure. Positive non‐lifting sign (OR 3.7, P = 0.004), lesion size <20 mm (OR 3.7, P < 0.001), LST‐NG type (OR 1.8, P = 0.034), and less colorectal ESD experience (OR 1.9, P = 0.016) were independent factors of slow‐speed dissection. Conclusions: ESD was feasible and safe for treating colorectal LSTs. Positive non‐lifting sign and tumor ≥20 mm indicated difficult ESD procedures. Technical failure was more likely to occur in lesions resected by less‐experienced endoscopists. Dissection speed might be improved with more experienced operators. [ABSTRACT FROM AUTHOR]

aims to analyze the endoscopic and pathological characteristics of colorectal laterally spreading tumors (LSTs) to assist malignant risk stratification to inform selection of the appropriate treatment strategy. Methods: Patients with colorectal LST were selected as retrospective study objects. Characteristics, including endoscopic findings and the most common site of LSTs of different diameters and histological types, were analyzed. The risk factors for malignancy in colorectal LST were explored by multivariate logistic regression analysis. Results: LSTs with diameters of ≥ 20 mm were found mainly in the rectum and mainly with granular-mixed (G-M) morphology (36% and 44.6%, respectively; p < 0.05), while LSTs with diameters of < 20 mm were found mainly in the ascending colon and mainly with granular-homogenous (G-H) morphology (40.9% and 46.2%, respectively; p < 0.05). Adenoma was the main histological type in patients with tumors of all diameters. However, the cancerization rate of LSTs was 31% in patients with tumor diameter ≥ 20 mm, while there was no invasive cancer in patients with tumor diameter < 20 mm. In the low-grade dysphasia (adenoma) group, most of the lesions were located in the ascending colon and most had the morphology LST-G-H (35.8% and 39.2%, respectively; p < 0.05). In the cancerization group, most of the lesions were located in the rectum, with the morphology LST-G-M (51.6% and 67.2%, respectively; p < 0.05), and the diameter was larger than that of the adenoma group (33.84 ± 17.99 mm vs 21.68 ± 8.99 mm). Conclusion: The rectum was the most common site for an LST with a diameter ≥ 20 mm and cancerization, of which the morphology was mainly LST-G-M (endoscopic submucosal dissection is the preferred treatment for this type of LST). LST malignancy was found to be correlated with lesion diameter, location, and morphological appearance. [ABSTRACT FROM AUTHOR]

Background: Colorectal laterally spreading tumors (LSTs) with malignant potential require en bloc resection by endoscopic submucosal dissection (ESD), but lesions with deep submucosal invasion (SMI) are endoscopically unresectable., Aim: To investigate the factors associated with high-grade dysplasia (HGD)/carcinoma and deep SMI in colorectal LSTs., Methods: The endoscopic and histological results of consecutive patients who underwent ESD for colorectal LSTs in our hospital from June 2013 to March 2019 were retrospectively analyzed. The characteristics of LST subtypes were compared. Risk factors for HGD/carcinoma and deep SMI (invasion depth ≥ 1000 μm) were determined using multivariate logistic regression., Results: A total of 323 patients with 341 colorectal LSTs were enrolled. Among the four subtypes, non-granular pseudodepressed (NG-PD) LSTs (85.5%) had the highest rate of HGD/carcinoma, followed by the granular nodular mixed (G-NM) (77.0%), granular homogenous (29.5%), and non-granular flat elevated (24.2%) subtypes. Deep SMI occurred commonly in NG-PD LSTs (12.9%). In the adjusted multivariate analysis, NG-PD [odds ratio (OR) = 16.8, P < 0.001) and G-NM (OR = 7.8, P < 0.001) subtypes, size ≥ 2 cm (OR = 2.2, P = 0.005), and positive non-lifting sign (OR = 3.3, P = 0.024) were independently associated with HGD/carcinoma. The NG-PD subtype (OR = 13.3, P < 0.001) and rectosigmoid location (OR = 8.7, P = 0.007) were independent risk factors for deep SMI., Conclusion: Because of their increased risk for malignancy, it is highly recommended that NG-PD and G-NM LSTs are removed en bloc through ESD. Given their substantial risk for deep SMI, surgery needs to be considered for NG-PD LSTs located in the rectosigmoid, especially those with positive non-lifting signs., Competing Interests: Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article., (©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.)