The First Prospective Randomized Study of the Removal of Large Benign Epithelial Neoplasms of the Colon by the EMR and ESD Method in Moscow, Russia.

Benign epithelial neoplasms of the colon are a significant problem of colorectal surgery and health care not only because of their malignant potential, but also because of their prevalence among the working-age population. Adenomas are more often detected in men than in women (OR = 1.77; 95% CI = 1.66-1.89), increasing in men from 25% at 50-54 years to 39% in people over 70 years old and in women from 15% at 50-54 years to 26% at 70 years of age (p < 0.001) [1]. Colonoscopy is the gold standard among all methods for diagnosing adenomas and adenocarcinomas of the colon. Endoscopic removal of colorectal polyps reduces the incidence and mortality from colorectal cancer (CRC) and is considered a necessary skill for all endoscopists performing colonoscopy [2, 6]. Endoscopic mucosal resection (EMR) was developed in 1984 by M. Tada et al. as a new technique for removing epithelial lesions of the gastrointestinal tract [181]. There are a number of aspects that cause additional complications during mucosectomy, such as convergence of folds, localization of large polyps between two folds, tumor spread beyond two folds, which are factors in tumor fragmentation and require additional study of their impact on long-term treatment outcomes. It is important to note that removal of colon tumors by fragmentation technique is associated with increased recurrence rate, however, in most cases these recurrent lesions are small in size and can be easily removed during dynamic colonoscopy. Predictably high recurrence rate during tumor fragmentation during removal indicates non-radical nature of the intervention performed and safety of this manipulation should be proven. Endoscopic submucosal dissection (ESD) is a relatively new method for removing superficial gastrointestinal neoplasms and was described at the end of the 20th century [85]. The development of the submucosal dissection technique was motivated by the difficulty of removing formations larger than 20 mm in a single block by endoscopic resection of the mucosa. Also, the association of tumor fragmentation during resection with a high risk of local recurrence and the difficulty of morphological evaluation of the removed specimen [133, 136, 190]. However, endoscopic submucosal dissection is a lengthy and energy-consuming procedure. According to Japanese authors, the average time for endoscopic submucosal dissection is 48.5-60 min. [77, 89], and, according to European scientists, the time for performing such interventions ranges from 142 to 176 minutes [7, 78, 144, 187]. According to Japanese clinical guidelines, the preferred method for removing large epithelial neoplasms of the colon with suspected intramucosal invasion is ESD, and European and American guidelines talk about the possible use of EMR, including in parts. In addition, unlike Japanese guidelines, where it is considered unsafe to remove a neoplasm in parts in assessing its radicality, Western guidelines allow the use of EMR in parts. Thus, endoscopic resection of the mucous membrane and endoscopic dissection in the submucosal layer are currently successfully used in the treatment of epithelial formations, but the advantages and disadvantages of each technique for a particular type of neoplasm, its histological nature and localization require systematization and clarification. The place of endoscopic mucosal resection and submucosal dissection in the removal of epithelial lesions of the colon has not been definitively established. Technical aspects, risk factors for complications, and long-term results of these types of endoscopic interventions require additional analysis.

Endoscopic interventions on the colon are accompanied by a certain percentage of complications. The most common complications of endoscopic removal of colon neoplasms are bleeding and perforation, the frequency of which varies from 0.08% to 10% depending on the analyzed method and patient sample [93, 120]. Given the wide variability of the available data, the influence of various factors on the frequency of complications requires additional study due to the need to identify correctable variables.

In June 2022, a group of authors proposed to the world community of specialists a new classification of complications in endoluminal endoscopy of the gastrointestinal tract for standardized assessment and analysis of the safety of endoscopic interventions [1] - "AGREE" (acronym for Adverse events GastRointEstinal Endoscopy) The authors of the classification also recommend recording any complications that arise, both at the stage of preparation for the planned endoscopic intervention (regardless of whether it was ultimately performed or not), and in those30 days after the intervention.[1]. It is these provisions of the AGREE classification that remain controversial and require more careful discussion [3]. In any case, in our opinion, at least a cause-and-effect relationship should be established between the action and the complication.