Endoscopic Assessment of Large Colorectal Lesions

Endoscopic submucosal dissection (ESD) has emerged as an important therapeutic strategy for colorectal lesions that cannot be resected en bloc using endoscopic mucosal resection or underwater endoscopic mucosal resection, enabling en bloc resection with precise histopathologic evaluation. However, the determination of appropriate indications for ESD of large colorectal lesions remains a significant challenge. This article aimed to provide a comprehensive summary of the indications for colorectal ESD and the role of endoscopic evaluation in formulating optimal treatment strategies. Colorectal lesions with deep submucosal invasion are often associated with extensive submucosal fibrosis, presenting considerable technical difficulties during ESD. Performing ESD on such lesions has been linked to an increased additional surgical intervention and a heightened risk of procedure-related complications. Therefore, thorough preoperative assessment of the lesion is essential to ensure an appropriate treatment strategy while minimizing unnecessary risks. Accurate evaluation of colorectal lesions through white-light imaging, advanced imaging modalities such as narrow-band imaging, and chromoendoscopy are critical for assessing lesion characteristics. Furthermore, the application of artificial intelligence in lesion characterization has shown potential as a supportive tool in facilitating clinical decision-making regarding the indications for ESD. Artificial intelligence may assist endoscopists by enhancing the accuracy of lesion assessment and contributing to improved treatment planning. A comprehensive understanding of the morphologic and pathologic features of large colorectal lesions is vital to identify patients who would benefit most from ESD, while minimizing the risk of complications. This review highlights the necessity of meticulous endoscopic evaluation to enable appropriate lesion selection, ensuring the safe and effective application of ESD for large colorectal lesions and ultimately contributing to improved patient outcomes.