Dynamic submucosal injection technique

AGA Clinical Practice Update on Endoscopic Lifting Agents: Commentary

DESCRIPTION

This American Gastroenterological Association (AGA) Institute Clinical Practice Update (CPU) reviews endoscopic lifting agents and their use in the gastrointestinal tract.

METHODS

This CPU was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership. This CPU underwent internal peer review by the Clinical Practice Updates Committee and external peer review through standard procedures of Clinical Gastroenterology and Hepatology. This expert commentary incorporates important as well as recently published data in this field and reflects the experiences of the authors.

Cold Snare Resection in the Colorectum: When to Choose it, When to Avoid it, and How to Do it

Cold snaring is now the preferred resection method for the majority of colorectal polyps encountered during colonoscopy. A key advantage of cold resection over resection utilizing electrocautery is a substantially lower risk of delayed hemorrhage. Cold snare resection is preferred for all lesions ≤10 mm and for nondysplastic sessile serrated lesions of any size but should be avoided when lesions have a significant risk of submucosal invasion or fibrosis. Cold snare resection can be considered for certain lesions 11-19 mm in size and some lateral spreading lesions ≥20 mm. This review discusses tips and techniques to optimize cold snare resection.

Endoscopic resection of large non-pedunculated colorectal polyps: current standards of treatment

Colorectal cancer is a significant public health concern, and large non-pedunculated colorectal polyps pose a substantial risk for malignancy and incomplete resection, which may lead to interval cancer. The choice of resection technique is influenced by various factors, including polyp size, morphology, location, submucosal invasion depth and endoscopist expertise. For non-cancerous superficial large non-pedunculated polyps, conventional hot or cold snare polypectomy, endoscopic mucosal resection and endoscopic submucosal dissection are common techniques for non-surgical therapeutic endoscopic resection of these polyps. This manuscript provides a comprehensive review of literature on current endoscopic resection techniques for large non-pedunculated colorectal polyps, emphasising indications, advantages, limitations and outcomes.

Curriculum for training in endoscopic mucosal resection in the colon: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement

Endoscopic mucosal resection (EMR) is the standard of care for the complete removal of large (≥ 10 mm) nonpedunculated colorectal polyps (LNPCPs). Increased detection of LNPCPs owing to screening colonoscopy, plus high observed rates of incomplete resection and need for surgery call for a standardized approach to training in EMR. 1 : Trainees in EMR should have achieved basic competence in diagnostic colonoscopy, < 10-mm polypectomy, pedunculated polypectomy, and common methods of gastrointestinal endoscopic hemostasis. The role of formal training courses is emphasized. Training may then commence in vivo under the direct supervision of a trainer. 2 : Endoscopy units training endoscopists in EMR should have specific processes in place to support and facilitate training. 3: A trained EMR practitioner should have mastered theoretical knowledge including how to assess an LNPCP for risk of submucosal invasion, how to interpret the potential difficulty of a particular EMR procedure, how to decide whether to remove a particular LNPCP en bloc or piecemeal, whether the risks of electrosurgical energy can be avoided for a particular LNPCP, the different devices required for EMR, management of adverse events, and interpretation of reports provided by histopathologists. 4: Trained EMR practitioners should be familiar with the patient consent process for EMR. 5: The development of endoscopic non-technical skills (ENTS) and team interaction are important for trainees in EMR. 6: Differences in recommended technique exist between EMR performed with and without electrosurgical energy. Common to both is a standardized technique based upon dynamic injection, controlled and precise snare placement, safety checks prior to the application of tissue transection (cold snare) or electrosurgical energy (hot snare), and interpretation of the post-EMR resection defect. 7: A trained EMR practitioner must be able to manage adverse events associated with EMR including intraprocedural bleeding and perforation, and post-procedural bleeding. Delayed perforation should be avoided by correct interpretation of the post-EMR defect and treatment of deep mural injury. 8: A trained EMR practitioner must be able to communicate EMR procedural findings to patients and provide them with a plan in case of adverse events after discharge and a follow-up plan. 9: A trained EMR practitioner must be able to detect and interrogate a post-endoscopic resection scar for residual or recurrent adenoma and apply treatment if necessary. 10: Prior to independent practice, a minimum of 30 EMR procedures should be performed, culminating in a trainer-guided assessment of competency using a validated assessment tool, taking account of procedural difficulty (e. g. using the SMSA polyp score). 11: Trained practitioners should log their key performance indicators (KPIs) of polypectomy during independent practice. A guide for target KPIs is provided in this document.

Polypectomy for Large Polyps with Endoscopic Mucosal Resection

Beginning in 1955, when the saline injection was first described to prevent transmural injury during polyp fulguration, endoscopic mucosal resection (EMR) has grown exponentially, both in scope and in practice. Because EMR is an organ-preserving technique even for large polyps, this allows for comparable outcomes to surgery, but substantially improved cost savings and significantly reduced morbidity and mortality. To achieve this, however, one must master the 4 fundamental components that are critical to the success of EMR- time, team, tools, and technique. This article aims to provide a compendium of state of the art updates within the field of endoluminal resection.

Hot snare polypectomy versus endoscopic mucosal resection for small colorectal polyps: a randomized controlled trial

BACKGROUND AND AIMS

This study was performed to compare endoscopic mucosal resection (EMR) with hot snare polypectomy (HSP) in terms of the complete resection rate and the incidence of adverse events for resecting small (5-10 mm) colorectal polyps.

METHODS

Small colorectal polyps (5-10 mm) with neoplastic features were randomly allocated to either the HSP or EMR group. A submucosal injection was performed prior to hot snaring in the EMR group only. Complete resection was defined as the absence of neoplastic tissue from two additional biopsies of the polypectomy site. R0 resection was defined as the absence of neoplastic tissue at the margin of the resected specimen.

RESULTS

A total of 362 colon polyps from 272 patients were included, and 167 polyps in the HSP group and 155 polyps in the EMR group were analyzed. Between the polypectomy techniques, there was no significant difference in the complete resection rates, which were 96.4% (161/167) in the HSP group and 95.5% (148/155) in the EMR group (P = 0.67). The R0 resection rate in the HSP and EMR groups was significantly different, with 49.7% (83/167) and 74.8% (116/155), respectively (P < 0.001). There was no significant difference in the incidence of adverse events between the two groups.

CONCLUSIONS

The complete resection rates for small (5-10 mm) polyps were not different between HSP and EMR.

TRIAL REGISTRY

ClincialTrials.gov number NCT02239536.

Review on colorectal endoscopic submucosal dissection focusing on the technical aspect

BACKGROUND

Endoscopic submucosal dissection (ESD) enables removal of broad-based colorectal polyps or lateral spreading tumors with a higher rate of en bloc resection and a lower risk of local recurrence. However, it is technically demanding. Over the past 20 years, various equipment and innovative techniques have been developed to reduce the difficulty of ESD. The information in the literature is scattered. Our aim is to provide a comprehensive review on the setup and technical aspects of colorectal ESD.

METHODS

We searched the PubMed database and systemically reviewed all original and review articles related to colorectal ESD. Further manual search according to reference lists of identified articles were done. The selected articles were categorized and reviewed. Original figures were created to help readers understand some of the ESD techniques.

RESULTS

A total of 216 articles were identified, in which 25 of them were review articles and 191 of them were original articles. They were categorized and reviewed. An in-depth appraisal of the setting, equipment, and technical aspects of colorectal ESD was performed.

CONCLUSIONS

Although ESD is a technically demanding procedure that requires expert endoscopic skills, it can be mastered. With good peri-procedural preparation, sufficient knowledge of the equipment, and thorough understanding of the useful endoscopic tricks and maneuvers, colorectal ESD can be performed smoothly and safely.

Impact of observational training on endoscopic mucosal resection outcomes and competency for large colorectal polyps: single endoscopist experience

Background and study aims  Endoscopic mucosal resection (EMR) is standard treatment for large colorectal polyps. However, it is a specialized technique with limited data on the effectiveness of training methods to acquire this skill. The aim of this study was to evaluate the impact of observational training on EMR outcomes and competency in an early-stage endoscopist. Patients and methods  A single endoscopist completed comprehensive EMR training, which included knowledge acquisition and direct observation of EMR cases, and proctored supervision, during the third year of gastroenterology fellowship. After training, EMR was independently attempted on 142 consecutive, large (i. e., ≥ 20 mm), non-pedunculated colorectal polyps between July 2014 and December 2017 (mean age 61.7 years; mean polyp size 30.4 mm; en-bloc resection 55 %). Surveillance colonoscopy for evaluation of residual neoplasia was available for 86 % of the cases. Three primary outcomes were evaluated: endoscopic assessment of complete resection, rate of adverse events (AEs), and rate of residual neoplasia on surveillance colonoscopy. Results  Complete endoscopic resection was achieved in 93 % of cases, the rates of AEs and residual neoplasia were 7.8 % and 7.3 %, respectively. The rate of complete resection remained stable (at 85 % or greater) with increasing experience while rates of AEs and residual neoplasia peaked and decreased after 60 cases. Conclusions  An early-stage endoscopist can acquire the skills to perform effective EMR after completing observational training. At least 60 independent EMRs for large colorectal polyps were required to achieve a plateau for clinically meaningful outcomes.

Solutions for submucosal injection: What to choose and how to do it

During the past decades, endoscopic resection techniques have gradually improved and gained more importance for the management of premalignant lesions and early cancers. These endoscopic resection techniques can be divided in 3 major groups: snare polipectomy, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). The use of submucosal injection is essential for the majority of EMR techniques and is an integral part of ESD, whereas during polipectomy it is not crucial in most cases except to prevent bleeding in large polyps and/or those with large stalks as an alternative to mechanical methods. Injection provides a lifting up effect of the lesion separating it from the muscular layer, thereby reducing thermal injury and the risk of perforation and bleeding while also facilitating en-bloc resection by improving technical feasibility. With this work, we aim to review the most common endoscopic resection techniques and the importance of submucosal injection in each one of them. For that, we present some of the most commonly used submucosal injection solutions, taking into account their advantages and disadvantages. We also discuss, based on current recommendations and our own experience, how and when to preform submucosal injection, depending on lesions features and endoscopic resection technique that´s being used, to assure complete resection and to prevent associated adverse events. Finally, we also present and discuss some new proposed submucosal injection solutions, endoscopic resection techniques and devices that may have a major impact on the future of therapeutic endoscopy.

Chromoendoscopy for Dysplasia Surveillance in Inflammatory Bowel Disease

Long-standing ulcerative colitis (UC) and extensive Crohn's colitis confer increased risk for development of colorectal cancer. Screening and surveillance colonoscopy programs aim to identify, resect, or detect dysplasia or colorectal cancer. Dysplastic lesions can be removed by endoscopic resection and patients with unresectable lesions can be referred for colectomy at an earlier stage, with the goal of reducing overall morbidity and mortality from colorectal cancer. Surveillance colonoscopy for patients with inflammatory bowel disease (IBD) is endorsed by multiple specialty societies. High-definition endoscopy systems provide improved image resolution, and application of dilute indigo carmine or methylene blue for chromoendoscopy can provide increased contrast. International specialty society guidelines differ in their recommendations regarding use of chromoendoscopy for dysplasia surveillance, with some guidelines advocating a risk-stratified surveillance strategy. In this review, we discuss chromoendoscopy technique, training, implementation, yield as compared with standard-definition and high-definition white light colonoscopy, and positioning of this technique in clinical practice.

Endoscopic submucosal injection of adipose-derived mesenchymal stem cells ameliorates TNBS-induced colitis in rats and prevents stenosis

Background

Mesenchymal stem cells have potential applications in inflammatory bowel disease due to their immunomodulatory properties. Our aim was to evaluate the feasibility, safety and efficacy of endoscopic administration of adipose-derived mesenchymal stem cells (ASCs) in a colitis model in rats.

Methods

Colitis was induced in rats by rectal trinitrobenzenesulfonic acid (TNBS). After 24 h ASCs (10⁷ cells) or saline vehicle were endoscopically injected into the distal colon. Rats were followed for 11 days. Daily weight, endoscopic score at days 1 and 11, macroscopic appearance at necropsy, colon length and mRNA expression of Foxp3 and IL-10 in mesenteric lymph nodes (MLN) were analyzed.

Results

Endoscopic injection was successful in all the animals. No significant adverse events or mortality due to the procedure occurred. Weight evolution was significantly better in the ASC group, recovering initial weight by day 11 (− 0.8% ± 10.1%, mean ± SD), whereas the vehicle group remained in weight loss (− 6.7% ± 9.2%, p = 0.024). The endoscopic score improved in the ASC group by 47.1% ± 5.3% vs. 21.8% ± 6.6% in the vehicle group (p < 0.01). Stenosis was less frequent in the ASC group (4.8% vs. 41.2%, p < 0.01). Colon length significantly recovered in the ASC group versus the vehicle group (222.6 ± 17.3 mm vs. 193.6 ± 17.9 mm, p < 0.001). The endoscopic score significantly correlated with weight change, macroscopic necropsy score and colon length. Foxp3 and IL-10 mRNA levels in MLN recovered with ASC treatment.

Conclusions

ASC submucosal endoscopic injection is feasible, safe and ameliorates TNBS-induced colitis in rats, especially stenosis.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0837-x) contains supplementary material, which is available to authorized users.

Update on Difficult Polypectomy Techniques

Endoscopists often encounter colon polyps that are technically difficult to resect. These lesions traditionally were managed surgically, with significant potential morbidity and mortality. Recent advances in endoscopic techniques and instruments have allowed endoscopists to safely and effectively remove colorectal lesions with high technical and clinical success and potentially avoid invasive surgery. Endoscopic mucosal resection (EMR) has gained acceptance as the first-line therapy for large colorectal lesions. Endoscopic submucosal dissection (ESD) has been reported to be associated with higher rate of en bloc resection and less risk of short-time recurrence, but with an increased risk of adverse events. Therefore, the role of colorectal ESD should be restricted to lesions with high-risk morphologic features of submucosal invasion. In this article, we review the recent literature on the endoscopic management of difficult colorectal neoplasms.

Endoscopy in the Diagnosis and Management of Complications of Inflammatory Bowel Disease

The role of endoscopy in inflammatory bowel disease (IBD) has grown over the last decade in both diagnostic and therapeutic realms. It aids in the initial diagnosis of the disease and also in the assessment of the extent and severity of disease. IBD is associated with development of multiple complications such as strictures, fistulae, and colon cancers. Endoscopy plays a pivotal role in the diagnosis of colon cancer in patients with IBD through incorporation of chromoendoscopy for surveillance. In addition, endoscopic resection with surveillance is recommended in the management of polypoid dysplastic lesions without flat dysplasia. IBD-associated benign strictures with obstructive symptoms amenable to endoscopic intervention can be managed with endoscopic balloon dilation both in the colon and small intestine. In addition, endoscopy plays a major role in assessing the neoterminal ileum after surgery to risk-stratify patients after ileocolonic resection and assessment of a patient with ileoanal pouch anastomosis surgery and management of postsurgical complications. Our article summarizes the current evidence in the role of endoscopy in the diagnosis and management of complications of IBD.

Endoscopic resection of colorectal lesions: The narrowing divide between East and West

Colonic polypectomy is an effective way of reducing colon cancer mortality. Multiple techniques now exist for the resection of polyps, and the endoscopist must decide on the appropriate resection approach for individual patients and lesions. This decision should maximize efficacy, safety and cost-effectiveness and provide optimal oncological outcomes while minimizing unnecessary surgical treatment. Advances in endoscopic imaging technology are improving the accuracy of endoscopic diagnosis and allowing more precise risk assessment of colonic lesions. Resection technique can be tailored to the endoscopic findings. Diminutive (≤5 mm) and small polyps (≤9 mm) are best resected primarily by snare techniques. Cold snare polypectomy has proven safety, but efficacy and technique require further study. There is variation in techniques used for polyps 6-20 mm in size and incomplete resection rates for conventional polypectomy may be considerable. Endoscopic mucosal resection (EMR) is well established, safe and effective for lesions without submucosal invasion (SMI); however, recurrence is a key limitation. Endoscopic submucosal dissection (ESD) is well established in the East; however, it is resource intensive and its role in lesions with a low risk of SMI is questionable. ESD in the West remains incompletely defined and is associated with high adverse event rates, but it is becoming increasingly available and successful as experience grows. Emerging full-thickness resection technologies are still in their infancy and remain experimental as a result of the absence of reliable closure devices and techniques. Patient-focused outcomes should guide technique selection.

Polidocanol injection decreases the bleeding rate after colon polypectomy: a propensity score analysis

BACKGROUND

EMR is the standard of care for the resection of large polyps.

OBJECTIVE

To compare the efficacy and safety profile of submucosal polidocanol injection with epinephrine-saline solution injection for colon polypectomy with a diathermic snare.

DESIGN

After 1-to-1 propensity score caliper matching, comparison of submucosal epinephrine injection was performed with polidocanol injection.

SETTING

Endoscopic suite at the University of Foggia between 2005 and 2014.

PATIENTS

Of 711 patients who underwent endoscopic resection of colon sessile polyps 20 mm or larger, 612 were analyzed after matching.

INTERVENTIONS

Submucosal epinephrine injection in 306 patients and polidocanol injection in 306 patients.

MAIN OUTCOME MEASUREMENTS

Univariate and multivariate logistic regression models aimed at identifying independent predictors of postpolypectomy bleeding (PPB).

RESULTS

The 2 groups presented similar baseline clinical parameters and lesion characteristics. All patients had a single polyp 20 mm or larger; the median size was 32 mm (interquartile range [IQR], 25-38) in the polidocanol group and 32 (IQR, 24-38) in the epinephrine group (P=.7). Polidocanol was more effective in preventing both immediate and delayed PPB (P<.001 and P=.003, respectively), and its efficacy was confirmed in almost all of the subgroups, regardless of polyp size and histology. Postprocedure perforation was observed in 2 patients (0.3%), both in the epinephrine group (P=.49). The 2 groups did not differ in the number of snare resections of lesions or the procedure duration (P=.24 and .6, respectively).

LIMITATIONS

Absence of randomization.

CONCLUSION

The submucosal injection of polidocanol for colon EMR is effective and significantly lowers the PPB rate.

Non-polypoid colorectal neoplasms: Classification, therapy and follow-up

In the last years, an increasing interest has been raised on non-polypoid colorectal tumors (NPT) and in particular on large flat neoplastic lesions beyond 10 mm tending to grow laterally, called laterally spreading tumors (LST). LSTs and large sessile polyps have a greater frequency of high-grade dysplasia and local invasiveness as compared to pedunculated lesions of the same size and usually represent a technical challenge for the endoscopist in terms of either diagnosis and resection. According to the Paris classification, NPTs are distinguished in slightly elevated (0-IIa, less than 2.5 mm), flat (0-IIb) or slightly depressed (0-IIc). NPTs are usually flat or slightly elevated and tend to spread laterally while in case of depressed lesions, cell proliferation growth progresses in depth in the colonic wall, thus leading to an increased risk of submucosal invasion (SMI) even for smaller neoplasms. NPTs may be frequently missed by inexperienced endoscopists, thus a careful training and precise assessment of all suspected mucosal areas should be performed. Chromoendoscopy or, if possible, narrow-band imaging technique should be considered for the estimation of SMI risk of NPTs, and the characterization of pit pattern and vascular pattern may be useful to predict the risk of SMI and, therefore, to guide the therapeutic decision. Lesions suitable to endoscopic resection are those confined to the mucosa (or superficial layer of submucosa in selected cases) whereas deeper invasion makes endoscopic therapy infeasible. Endoscopic mucosal resection (EMR, piecemeal for LSTs > 20 mm, en bloc for smaller neoplasms) remains the first-line therapy for NPTs, whereas endoscopic submucosal dissection in high-volume centers or surgery should be considered for large LSTs for which en bloc resection is mandatory and cannot be achieved by means of EMR. After piecemeal EMR, follow-up colonoscopy should be performed at 3 mo to assess resection completeness. In case of en bloc resection, surveillance colonoscopy should be scheduled at 3 years for adenomatous lesions ≥ 1 cm, or in presence of villous features or high-grade dysplasia patients (regardless of the size), while less intensive surveillance (colonoscopy at 5-10 years) is needed in case of single (or two) NPT < 1 cm presenting tubular features or low-grade dysplasia at histology.

Foregut and colonic perforations: practical measures to prevent and assess them

Acute endoscopic perforations of the foregut and colon are rare but can have devastating consequences. There are several principles and practices that can lower the risk of perforation and guide the endoscopist in early assessment when they do occur. Mastery of these principles will lead to overall improved patient outcomes.

Endoscopic management of nonpolypoid colorectal lesions in colonic IBD

Much of the flat or biopsy-only detected dysplasia in inflammatory bowel disease (IBD) that had historically warranted a colectomy can now be shown to be circumscribed lesions with dye-spray or advanced endoscopic imaging. These lesions are therefore amenable to endoscopic excision with close endoscopic follow-up, though are technically very challenging. This review discusses preresection assessment of nonpolypoid or flat (Paris 0-II) lesions in colitis; lifting with colloids or hyaluronate; endoscopic mucosal resection (EMR) with spiral or flat ribbon snares; or simplified, hybrid, and full endoscopic submucosal dissection (ESD); as well as mucosal ablation. Close follow-up postresection is mandatory.

An atlas of the nonpolypoid colorectal neoplasms in inflammatory bowel disease

The role of endoscopy in the management of patients with inflammatory bowel disease (IBD) is well established. However, recent data have shown significant limitations in the effectiveness of colonoscopy in preventing colorectal cancer (CRC) in patients with IBD colitis. The current standard random biopsy seemed largely ineffective in detecting nonpolypoid colorectal neoplasms. Data using chromoendoscopy with targeted biopsy, however, showed a significant improvement when used to detect dysplasia, the best predictor of CRC risk. This article provides a useful and organized series of images of the detection, diagnosis and management of the superficial elevated, flat, and depressed colorectal neoplasms in IBD patients, and provides a technical guide for the use of chromoendoscopy with targeted biopsy.

Establishing a rabbit model of malignant esophagostenosis using the endoscopic implantation technique for studies on stent innovation

BACKGROUND

Stents are recommended in patients with dysphagia caused by esophageal stricture, but an ideal stent does not currently exist. Thus, studies on new esophageal stents are necessary, and suitable animal models are desperately needed for these studies. The aim of this study was to establish a model of malignant esophageal stricture in rabbit for studies on stent innovation.

METHODS

A total of 38 New Zealand white rabbits were used in this study. Using the endoscopic submucosal injection technique, VX2 fragments were inoculated into the submucosal layer of the rabbit thoracic esophagus, and an endoscopic follow-up was subsequently performed to observe the tumor development and progression. The self-expandable metal stents were randomly deployed in rabbits with severe esophageal stricture to investigate the safety and feasibility of the animal models for stenting.

RESULTS

An endoscopic implantation procedure for VX2 tumors was completed in 34/38 rabbits, and tumor development was confirmed in 30/34 animals. The success rate of the endoscopic implantation and tumor development were 89.4% (95% CI, 79.6% to 99.2%) and 88.2% (95% CI, 76.9% to 99.5%) respectively. During the endoscopic follow-up period, severe esophageal stricture occurred in 22/30 rabbits with a rate of 73.3% (95% CI, 57.5% to 89.1%), and 12/22 models received stent placement. During and after stent implantation, no severe stent-related complication or mortality occurred in the animal models. The rabbits that received stent placement survived longer than those without stent implantation (the mean survival time: 53.9 days versus 40.3 days, P = 0.016).

CONCLUSION

The endoscopic method is a safe and effective method for establishing a malignant esophagostenosis model in rabbits. This model can simulate the human body environment for stent deployment and is an excellent tool for the study of stent innovation for the treatment of esophageal cancer.

Advanced endoscopic resection in the colon: recent innovations, current limitations and future directions

The major health burden of colorectal cancer is reduced by colonoscopic polypectomy. The majority of polyps encountered are diminutive in size and easily removed; however, endoscopic removal of lesions >20 mm in size is also effective and safe. Techniques have progressed, advancing the boundaries of endoscopic therapy to include resection of circumferential lesions and selected submucosal invasive cancers. While there are cost and safety advantages over surgical management, specific limitations of endoscopic resection remain, chiefly bleeding, perforation and recurrence. Recent studies highlight the utility of risk stratification and demonstrate the effectiveness of endoscopic treatment of complications; however, strategies for prevention remain elusive. Prediction of submucosal invasive cancers through systematic assessment of lesion morphology and surface pattern is now established. Harnessing submucosal invasive cancer prediction and risk stratification allows a shift toward lesion-specific therapy, the next paradigm in the management of advanced colonic lesions.

Comparison of endoscopic submucosal implantation vs. surgical intramuscular implantation of VX2 fragments for establishing a rabbit esophageal tumor model for mimicking human esophageal squamous carcinoma

Purpose

This study was undertaken to establish a rabbit esophageal tumor model for mimicking human esophageal squamous carcinoma (ESC) by endoscopic and surgical implantation of VX2 tumors.

Methods

Fragments of a VX2 tumour were endoscopically implanted in the submucosal layer of the thoracic esophagus of 32 New Zealand white rabbits, while 34 animals received surgical implantation into the muscular layer. Then, the animals were studied endoscopically and pathologically. The safety and efficiency of the two methods and the pathological features of the animal models were analyzed.

Results

Both the endoscopic and the surgical method had a relatively high success rate of tumor implantation [93.7% (30/32) vs. 97.1% (33/34)] and tumor growth [86.7% (26/30) vs. 81.8% (27/33)], and the variation in the results was not statistically significant (P>0.05). Compared with those produced by the surgical method, the models produced by the endoscopic method had a higher rate of severe esophageal stricture [61.5% (16/26) vs. 29.6% (8/27)] and of intra-luminal tumor growth [73.1% (19/26) vs. 37.0% (10/27)], and had a lower rate of tumor invasion of adjacent organs [53.8% (14/26) vs. 81.5% (22/27)]; all of these results were statistically significant (P<0.05). However, the difference in the survival time and the rates of tumor regional/distant metastasis [38.5% (10/26) vs. 51.8% (14/27)] between the two methods were not statistically significant (P>0.05).

Conclusion

The endoscopic and surgical methods are both safe and effective for establishment of VX2 tumors in the rabbit esophagus. The models produced by the two methods have different pathologic features mimicking that of human ESC. We recommend the models for studies on surgical procedures and minimally invasive treatments.

Outcomes of repeat colonoscopy in patients with polyps referred for surgery without biopsy-proven cancer

BACKGROUND

Despite advances in endoscopic treatment, many colonic adenomas are still referred for surgical resection. There is a paucity of data on the suitability of these lesions for endoscopic treatment.

OBJECTIVE

To analyze the results of routine repeat colonoscopy in patients referred for surgical resection of colon polyps without biopsy-proven cancer.

DESIGN

Retrospective review.

SETTING

University hospital.

PATIENTS

Patients referred to a colorectal surgeon for surgical resection of a polyp without biopsy-proven cancer.

INTERVENTIONS

Repeat colonoscopy.

MAIN OUTCOME MEASUREMENTS

The rate of successful endoscopic treatment.

RESULTS

There were 38 lesions in 36 patients; 71% of the lesions were noncancerous and were successfully treated endoscopically. In 26% of the lesions, previous removal was attempted by the referring physician but was unsuccessful. The adenoma recurrence rate was 50%, but all recurrences were treated endoscopically and none were cancerous. Two patients were admitted for overnight observation. There were no major adverse events.

LIMITATIONS

Single center, retrospective.

CONCLUSIONS

In the absence of biopsy-proven invasive cancer, it is appropriate to reevaluate patients referred for surgical resection by repeat colonoscopy at an expert center.

Advanced endoscopic resection of colorectal lesions

Advanced endoscopic resection techniques allow curative treatment of difficult colonic lesions and avoid the need for surgery in certain cases. If endoscopic resection is indicated, the choice of the most appropriate resection technique depends on lesion characteristics and endoscopist expertise.

Endoscopic resection of large colon polyps

Endoscopic resection, including polypectomy, endoscopic mucosal resection, and endoscopic submucosal dissection, is the preferred treatment method of large colorectal polyps. Its safety and efficacy have been shown. Endoscopic removal techniques are important because they provide a resection specimen for precise histopathologic staging to further direct diagnosis, prognosis, and management decisions. Used according to its indications, it provides curative resection and obviates the higher morbidity, mortality, and cost associated with alternative surgical treatment.