Endoscopic management of colorectal adenomas

Endoscopic mucosal resection and endoscopic submucosal dissection with an external additional working channel (EMR+ and ESD+) are equivalent to using a double-channel endoscope: a systematic evaluation in a porcine ex vivo model

BACKGROUND AND AIMS

With an external additional working channel (AWC) endoscopic mucosal resection (EMR) as well as endoscopic submucosal dissection (ESD) can be extended to techniques termed "EMR+" and "ESD+." These novel techniques are systematically compared to EMR and ESD under the use of a double-channel endoscope (DC).

METHODS

Our trial was conducted prospectively in a pre-clinical porcine animal model (EASIE-R simulator) with standardized gastric lesions measuring 3 or 4 cm.

RESULTS

EMR+ and EMR DC showed both good results for 3 cm lesions with no adverse events and an en bloc resection rate of 73.33% (EMR+) and 60.00% (EMR DC, p = 0.70). They came to their limits in 4 cm lesions with muscularis damages of 20.00% (EMR+), 13.33% (EMR DC, p ≥ 0.99) and decreasing en bloc resection rates of 60.00% (EMR+) and 46.67% (EMR DC, p = 0.72). ESD+ and ESD DC were both reliable concerning en bloc resection rates (100% in all groups) and adverse events (0.00% in 3 cm lesions, 12.50% muscularis damages in both ESD+ and ESD DC in 4 cm lesions). Resection time was slightly shorter in all groups with the AWC compared to DC although only reaching significance in 3 cm ESD lesions (p < 0.05*).

CONCLUSIONS

With the AWC, a standard endoscope can easily be transformed to double-channel functionality. We could show that EMR+ and ESD+ are non-inferior to EMR and ESD under the use of a double-channel endoscope. Consequently, the AWC presents an affordable alternative to a double-channel endoscope for both EMR and ESD.

A step-by-step guide to approaching colon polyps

Colorectal cancer (CRC) is considered one of the most prevalent cancers among Iranian men and women (1). Colorectal polyps, known as precursors of CRCs, are of great importance. Surveillance, locating, and removal of colorectal polyps make them the most modifiable factor apart from other genetic and environmental factors leading to CRCs. Colorectal polyps are defined as outpouchings from superficial and deep layers of mucosa of the colonic wall. They are classified as adenomas, serrated polyps, hyperplastic polyps, and hamartomas based on histological evaluation. Submucosal invasion precludes the possibility of endoscopic resection and should be ruled out via colonoscopic evaluation (2). Knowing this significance, the present study aims to present a brief review on classification, probability of endoscopic resection, complications of endoscopic polypectomy, as well as proper surveillance after polypectomy.

Endoscopic submucosal dissection with an additional working channel (ESD+): a novel technique to improve procedure time and safety of ESD

Background and aims

A new external additional working channel (AWC) was recently introduced by which endoscopic submucosal dissection (ESD) can be converted to a technique termed “ESD+ ”. We aim to systematically evaluate this novel technique in flat gastric lesions and compare it to classical ESD.

Methods

The study was prospectively conducted in a pre-clinical ex vivo animal model (EASIE-R simulator) with porcine stomachs. Prior to intervention, we set standardized lesions measuring 3 cm or 4 cm in antegrade as well as in retrograde positions.

Results

Overall, 64 procedures were performed by an experienced endoscopist. Both techniques were reliable and showed en bloc resection rates of 100%. Overall, ESD+ reduced time of procedure compared to ESD (24.5 vs. 32.5 min, p = 0.025*). Particularly, ESD+ was significantly faster in retrograde lesions with a median of 22.5 vs. 34.0 min in 3 cm retrograde lesions (p = 0.002*) and 34.5 vs. 41.0 min (p = 0.011*) in 4 cm retrograde lesions. There were 0 perforations with both techniques. In ESD+ , 1 muscularis damage occurred (3.13%) compared to 6 muscularis damages with ESD (18.75%, p = 0.045*).

Conclusions

By its grasp-and-mobilize technique, ESD+ allows potentially faster and safer resections of flat gastric lesions compared to conventional ESD in an ex vivo porcine model. The potential advantages of ESD+ in terms of procedure time may be particularly relevant for difficult lesions in retrograde positions.

Electronic supplementary material

The online version of this article (10.1007/s00464-020-07808-w) contains supplementary material, which is available to authorized users.

Endoscopic mucosal resection with an additional working channel (EMR+) in a porcine ex vivo model: a novel technique to improve en bloc resection rate of snare polypectomy

Background and study aims  Recently, a new external additional working channel (AWC) was introduced by which conventional endoscopic mucosal resection (EMR) can be improved to a technique termed "EMR+". We first evaluated this novel technique in comparison to classical EMR in flat lesions. Methods  The trial was prospectively conducted in an ex vivo animal model with porcine stomachs placed into the EASIE-R simulator. Prior to intervention, standardized lesions were set by coagulation dots, measuring 1, 2, 3 or 4 cm. Results  Overall, 152 procedures were performed. EMR and EMR+ were both very reliable in 1-cm lesions, each showing en bloc resection rates of 100 %. EMR+ en bloc resection rate was significantly higher in 2-cm lesions (95.44 % vs. 54.55 %, P  = 0.02), in 3-cm lesions (86.36 % vs. 18.18 %, P  < 0.01) and also in 4-cm lesions (60.00 % vs. 0 %, P  < 0.01). Perforations occurred only in EMR+ procedures in 4-cm lesions (3 of 20; 15 %). Conclusions  With its grasp-and-snare technique, EMR+ facilitates en bloc resection of larger lesions compared to conventional EMR. In lesions 2 cm and larger, EMR+ has demonstrated advantages, especially concerning en bloc resection rate. At 3 cm, EMR+ reaches its best discriminatory power whereas EMR+ has inherent limits at 4 cm and in lesions of that size, other techniques such as ESD or surgery should be considered.

Importance of Resection Margins in the Treatment of Rectal Adenomas by Transanal Endoscopic Surgery

BACKGROUND

Polypectomy is the gold standard for treating colorectal adenomas up to 2 cm in size. For larger lesions, various procedures ranging from endoscopy to transanal surgery can be performed and achieve varying results for en bloc resection and recurrence. There are no clear guidelines for dealing with involved resection margins. We assess the recurrence of rectal adenomas operated using TEM with full-thickness wall excision with or without free resection margins and define optimal endoscopic follow-up.

METHOD

Observational study with prospective data collection, including patients undergoing TEM between 6/2004 and 11/2017, with definitive diagnosis of rectal adenoma. Data on epidemiological, preoperative, surgical, postoperative, pathological, and follow-up variables were recorded. Univariate analysis, follow-up risk function, and multivariate logistic regression analysis were performed to detect risk factors for recurrence.

RESULTS

TEM was indicated in 736 patients; 481 adenomas were identified in the preoperative biopsy, of which 95 were infiltrating adenocarcinomas (19.8%) in the definitive pathology study. With a minimum follow-up of 1 year, 372 patients were included. Pathology study showed free margins in 324 (87%). Recurrences were recorded in 15 patients (4%), up to 18 months in the free margins group and up to 24 months in the involved margins group. Thirteen patients with recurrence (86.6%) were treated with TEM. No predictors of recurrence were found in the multivariate analysis.

CONCLUSION

TEM is the technique of choice for treating rectal adenomas and recurrences, achieving a low relapse rate. Follow-up must be adapted to resection margins and should be extended to 24 months.

Importance of Resection Margins in the Treatment of Rectal Adenomas by Transanal Endoscopic Surgery

BACKGROUND

Polypectomy is the gold standard for treating colorectal adenomas up to 2 cm in size. For larger lesions, various procedures ranging from endoscopy to transanal surgery can be performed and achieve varying results for en bloc resection and recurrence. There are no clear guidelines for dealing with involved resection margins. We assess the recurrence of rectal adenomas operated using TEM with full-thickness wall excision with or without free resection margins and define optimal endoscopic follow-up.

METHOD

Observational study with prospective data collection, including patients undergoing TEM between 6/2004 and 11/2017, with definitive diagnosis of rectal adenoma. Data on epidemiological, preoperative, surgical, postoperative, pathological, and follow-up variables were recorded. Univariate analysis, follow-up risk function, and multivariate logistic regression analysis were performed to detect risk factors for recurrence.

RESULTS

TEM was indicated in 736 patients; 481 adenomas were identified in the preoperative biopsy, of which 95 were infiltrating adenocarcinomas (19.8%) in the definitive pathology study. With a minimum follow-up of 1 year, 372 patients were included. Pathology study showed free margins in 324 (87%). Recurrences were recorded in 15 patients (4%), up to 18 months in the free margins group and up to 24 months in the involved margins group. Thirteen patients with recurrence (86.6%) were treated with TEM. No predictors of recurrence were found in the multivariate analysis.

CONCLUSION

TEM is the technique of choice for treating rectal adenomas and recurrences, achieving a low relapse rate. Follow-up must be adapted to resection margins and should be extended to 24 months.

Multimodal endoscopic system based on multispectral and photometric stereo imaging and analysis

We propose a multimodal endoscopic system based on white light (WL), multispectral (MS), and photometric stereo (PS) imaging for the examination of colorectal cancer (CRC). Recently, the enhancement of the diagnostic accuracy of CRC colonoscopy has been reported; however, tumor diagnosis for a variety of lesion types remains challenging using current endoscopy. In this study, we demonstrate that our developed system can simultaneously discriminate tumor distributions and provide three-dimensional (3D) morphological information about the colon surface using the WL, MS, and PS imaging modalities. The results demonstrate that the proposed system has considerable potential for CRC diagnosis.

Colorectal cancer: genetic abnormalities, tumor progression, tumor heterogeneity, clonal evolution and tumor-initiating cells

Colon cancer is the third most common cancer worldwide. Most colorectal cancer occurrences are sporadic, not related to genetic predisposition or family history; however, 20-30% of patients with colorectal cancer have a family history of colorectal cancer and 5% of these tumors arise in the setting of a Mendelian inheritance syndrome. In many patients, the development of a colorectal cancer is preceded by a benign neoplastic lesion: either an adenomatous polyp or a serrated polyp. Studies carried out in the last years have characterized the main molecular alterations occurring in colorectal cancers, showing that the tumor of each patient displays from two to eight driver mutations. The ensemble of molecular studies, including gene expression studies, has led to two proposed classifications of colorectal cancers, with the identification of four/five non-overlapping groups. The homeostasis of the rapidly renewing intestinal epithelium is ensured by few stem cells present at the level of the base of intestinal crypts. Various experimental evidence suggests that colorectal cancers may derive from the malignant transformation of intestinal stem cells or of intestinal cells that acquire stem cell properties following malignant transformation. Colon cancer stem cells seem to be involved in tumor chemoresistance, radioresistance and relapse.