Advances, problems, and complications of polypectomy

Colo-colonic intussusception with post-polypectomy electrocoagulation syndrome: A case report

BACKGROUND

Post-polypectomy electrocoagulation syndrome (PPES) can occur after colonoscopic polypectomy and is usually treated conservatively with a positive prognosis. Nevertheless, there can be cases with complications developing.

CASE SUMMARY

A 58-year-old woman, who had no previous medical history, visited the Emergency Department of another hospital with symptoms of abdominal pain and fever, 1 d after multiple colonoscopic polypectomies. An abdominopelvic computed tomography (CT) scan demonstrated colo-colonic intussusception, and she was transferred to our hospital to consider an operation. CT showed colo-colonic intussusception with PPES and no evidence of obstruction. The physical examination showed localized mild tenderness on the right sided abdomen. The patient fasted and was admitted for treatment with intravenous antibiotics (piperacillin/tazobactam 4.5 g each 8 h, ornidazole 500 mg each 12 h). After admission, the symptoms got better and a follow-up CT scan demonstrated resolution of the PPES and intussusception. The patient was discharged on hospital day 9.

CONCLUSION

Colo-colic intussusception can occur with PPES, and it can be properly treated conservatively.

Modified endoscopic mucosal resection techniques for treating precancerous colorectal lesions

Endoscopic mucosal resection (EMR) is a technique allowing efficacious and minimally invasive resection of precancerous lesions across the entire gastrointestinal tract. However, conventional EMR, involving injection of fluid into the submucosal space, is imperfect, given the high rate of recurrence of post-endoscopic resection adenoma, especially after piecemeal resection. In light of these observations, modifications of the technique have been proposed to overcome the weakness of conventional EMR. Some of them were designed to maximize the chance of en bloc resection—cap-assisted EMR, underwater EMR, tip-in EMR, precutting, assisted by ligation device—while others were designed to minimize the complications (cold EMR). In this review, we present their modes of action and summarize the evidence regarding their efficacy and safety.

Cold loop polypectomy perforation of a tiny colon polyp

We report the case of a 61-year-old woman having corticoid treatment with corticosteroids for polyarthralgia, who underwent a post-polypectomy surveillance colonoscopy, identifying a 5-mm diameter, flat-elevated polyp in the proximal transverse colon (Paris 0-IIa).

Endoscopic resection is more effective than biopsy or EUS to detect residual rectal neuroendocrine tumor

Background and study aims  Rectal neuroendocrine tumors (NETs) are often discovered incidentally and may be misidentified as adenomatous polyps. This can result in a partial resection at the index procedure, and lesions are often referred for staging or evaluation for residual disease at the resection site. The aim of this study was to identify the ideal method to confirm complete excision of small rectal NETs. Patients and methods  Data from patients with a previously resected rectal NET referred for follow-up endoscopy or endoscopic ultrasound (EUS) were retrospectively reviewed. Univariate analysis was performed on categorical data using the Chi-squared test. Results  Forty-nine patients with rectal NETs were identified by pathology specimens. Of those, 39 underwent follow-up endoscopy or EUS and were included. Baseline characteristics included gender (71 % F, 29 % M), age (57.2 ± 13.4 yrs) lesion size (7.3 ± 4.2 mm) and location. The prior resection site was identified in 37/39 patients who underwent tissue sampling. Residual NET was found histologically in 14/37 lesions. All residual disease was found during salvage endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) and 43 % had a normal-appearing scar. Every patient undergoing EUS had an unremarkable exam. Initial cold biopsy polypectomy ( P  = 0.006), visible lesions ( P  = 0.001) and EMR/ESD of the prior resection site ( P  = 0.01) correlated with residual NET. Conclusions  Localized rectal NETs may be incompletely removed with standard polypectomy. If an advanced resection is not performed initially, repeat endoscopy with salvage EMR or ESD of the scar should be considered. For small rectal NETs, biopsy may miss residual disease when there is no visible lesion and EUS appears to have no benefit.

Improving Colonoscopy Lesion Classification Using Semi-Supervised Deep Learning

While data-driven approaches excel at many image analysis tasks, the performance of these approaches is often limited by a shortage of annotated data available for training. Recent work in semi-supervised learning has shown that meaningful representations of images can be obtained from training with large quantities of unlabeled data, and that these representations can improve the performance of supervised tasks. Here, we demonstrate that an unsupervised jigsaw learning task, in combination with supervised training, results in up to a 9.8% improvement in correctly classifying lesions in colonoscopy images when compared to a fully-supervised baseline. We additionally benchmark improvements in domain adaptation and out-of-distribution detection, and demonstrate that semi-supervised learning outperforms supervised learning in both cases. In colonoscopy applications, these metrics are important given the skill required for endoscopic assessment of lesions, the wide variety of endoscopy systems in use, and the homogeneity that is typical of labeled datasets.

The quality of colorectal polypectomy. Is it enough to have just a visual assessment of the site?

INTRODUCTION

Performing a colonoscopy allows the examination of the entire colon and the assessment of polyps.

PATIENTS, MATERIALS AND METHODS

We performed a retrospective analysis of prospectively collected data from January 2018 until February 2020 (two years), in which we enrolled a number of 210 patients performing colonoscopy in the Research Center of Gastroenterology and Hepatology, University of Medicine and Pharmacy of Craiova, Romania. We performed 326 polypectomies.

RESULTS

We classified the polyps into diminutive (n=169), small (n=103) and large polyps (n=54). Regarding the polypectomy technique, our results indicated that 40 out of 48 (83.3%) polypectomies with the biopsy forceps were complete, as well as 27 out of 31 (87.1%) cold snare polypectomies and 12 out of 14 (85.7%) hot snare polypectomies. The differences were not statistically significant (p=0.116). Regarding the number of incomplete polypectomies, our data suggests that the high expertise endoscopist had two incomplete resections (5.1% of total), the medium expertise endoscopist 1 had also two incomplete resections (11.1% of total), the medium expertise endoscopist 2 had three incomplete resections (15% of total), the limited expertise endoscopist 1 had three incomplete resections (27.27% of total) and the limited expertise endoscopist 2 had four incomplete resections (30.76% of total). Analyzing the data, the differences were statistically significant (p=0.006).

CONCLUSIONS

Our study is able to suggest that high-definition white-light endoscopy (HD-WLE) macroscopic visualization of the polyp resection site is not enough to assess complete polyp resection and follow-up colonoscopy should be performed for cases with incomplete margins of resection.

Design of an Impedance-Controlled Hot Snare Polypectomy Device

This paper goes through the process of first designing a feedback system that allows for the measuring of impedance while using the hot snare polypectomy method. The electrosurgical unit used in this study was the Olympus PSD-30. After the impedance-controlled feedback system was completed, the device was tested under a range of power settings from 10 W-50 W. The test was performed ex vivo using porcine colon samples. Using the information gathered from these tests, a technique of determining the threshold of perforation and implementing a system to automatically stop the applied current from the PSD-30 was developed. The data showed that after an increase in impedance of 25% from that of the initially measured impedance, perforation ensued in the tissue samples. Using this information, the device was programmed to interrupt the PSD-30 at this threshold point. This final design was tested and proved able to automatically prevent the event of perforation from occurring, resulting in the ability to prevent serious complications.

Colonoscopy: Advanced and Emerging Techniques-A Review of Colonoscopic Approaches to Colorectal Conditions

A complete colonoscopy is key in the diagnostic and therapeutic approaches to a variety of colorectal diseases. Major challenges are incomplete polyp removal and missed polyps, particularly in the setting of a difficult colonoscopy. There are a variety of both well-established and newer techniques that have been developed to optimize polyp detection, perform complete polypectomy, and endoscopically treat various complications and conditions such as strictures and perforations. The objective of this article is to familiarize the colorectal surgeon with techniques utilized by advanced endoscopists.

An international survey of polypectomy training and assessment

Background and study aims Colonic polypectomy is acknowledged to be a technically challenging part of colonoscopy. Training in polypectomy is recognized to be often inconsistent. This study aimed to ascertain worldwide practice in polypectomy training. Patients and methods An electronic survey was distributed to endoscopic trainees and trainers in 19 countries asking about their experiences of receiving and delivering training. Participants were also asked about whether formal polypectomy training guidance existed in their country. Results Data were obtained from 610 colonoscopists. Of these responses, 348 (57.0 %) were from trainers and 262 (43.0 %) from trainees; 6.6 % of trainers assessed competency once per year or less often. Just over half (53.1 %) of trainees had ever had their polypectomy technique formally assessed by any trainer. Approximately half the trainees surveyed (51.1 %) stated that the principles of polypectomy had only ever been taught to them intermittently. Of those trainees with the most colonoscopy experience, who had performed over 500 procedures, 48.2 % had had training on removing large polyps of over 10 mm; 46.2 % (121 respondents) of trainees surveyed held no record of the polypectomies they had performed. Only four of the 19 countries surveyed had specific guidelines on polypectomy training. Conclusions A significant number of competent colonoscopists have never been taught how to perform polypectomy. Training guidelines worldwide generally give little direction as to how trainees should acquire polypectomy skills. The learning curve for polypectomy needs to be defined to provide reliable guidance on how to train colonoscopists in this skill.

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.

Post-Colonoscopy Complications: A Systematic Review, Time Trends, and Meta-Analysis of Population-Based Studies

OBJECTIVES

Many studies around the world addressed the post-colonoscopy complications, but their pooled prevalence and time trends are unknown. We performed a systematic review and meta-analysis of population-based studies to examine the pooled prevalence of post-colonoscopy complications ("perforation", "bleeding", and "mortality"), stratified by colonoscopy indication. Temporal variability in the complication rate was assessed.

METHODS

We queried Pubmed, Embase, and the Cochrane library for population-based studies examining post-colonoscopy complications (within 30 days), performed from 2001 to 2015 and published by 1 December 2015. We determined pooled prevalence of perforations, post-colonoscopy bleeding, post-polypectomy bleeding, and mortality.

RESULTS

We retrieved 1,074 studies, of which 21 met the inclusion criteria. Overall, pooled prevalences for perforation, post-colonoscopy bleeding, and mortality were 0.5/1,000 (95% confidence interval (CI) 0.4-0.7), 2.6/1,000 (95% CI 1.7-3.7), and 2.9/100,000 (95% CI 1.1-5.5) colonoscopies. Colonoscopy with polypectomy was associated with a perforation rate of 0.8/1,000 (95% CI 0.6-1.0) and a post-polypectomy bleeding rate of 9.8/1,000 (95% CI 7.7-12.1). Complication rate was lower for screening/surveillance than for diagnostic examinations. Time-trend analysis showed that post-colonoscopy bleeding declined from 6.4 to 1.0/1,000 colonoscopies, whereas the perforation and mortality rates remained stable from 2001 to 2015. Overall, considerable heterogeneity was observed in most of the analyses.

CONCLUSIONS

Worldwide, the post-colonoscopy complication rate remained stable or even declined over the past 15 years. The findings of this meta-analysis encourage continued efforts to achieve and maintain safety targets in colonoscopy practice.

Aberrant Gene Expression Profile of Unaffected Colon Mucosa from Patients with Unifocal Colon Polyp

Background

The aim of this study was to evaluate gene expression profiles in unaffected colon mucosa and polyp tissue from patients with unifocal colon polyp to investigate the potential mucosa impairment in normal-appearing colon mucosa from these patients.

Material/Methods

Colon polyp patients were prospectively recruited. We obtained colon biopsies from the normal-appearing sites and polyp tissue through colonoscopy. Gene expression analysis was performed using microarrays. Gene ontology and clustering were evaluated by bioinformatics.

Results

We detected a total of 711 genes (274 up-regulated and 437 down-regulated) in polyp tissue and 256 genes (170 up-regulated and 86 down-regulated) in normal-appearing colon mucosa, with at least a 3-fold of change compared to healthy controls. Heatmapping of the gene expression showed similar gene alteration patterns between unaffected colon mucosa and polyp tissue. Gene ontology analyses confirmed the overlapped molecular functions and pathways of altered gene expression between unaffected colon mucosa and polyp tissue from patients with unifocal colon polyp. The most significantly altered genes in normal-appearing tissues in polyp patients include immune response, external side of plasma membrane, nucleus, and cellular response to zinc ion.

Conclusions

Significant gene expression alterations exist in unaffected colon mucosa from patients with unifocal colon polyp. Unaffected colon mucosa and polyp tissue share great similarity and overlapping of altered gene expression profiles, indicating the potential possibility of recurrence of colon polyps due to underlying molecular abnormalities of colon mucosa in these patients.

Coagulation syndrome: Delayed perforation after colorectal endoscopic treatments

Various procedure-related adverse events related to colonoscopic treatment have been reported. Previous studies on the complications of colonoscopic treatment have focused primarily on perforation or bleeding. Coagulation syndrome (CS), which is synonymous with transmural burn syndrome following endoscopic treatment, is another typical adverse event. CS is the result of electrocoagulation injury to the bowel wall that induces a transmural burn and localized peritonitis resulting in serosal inflammation. CS occurs after polypectomy, endoscopic mucosal resection (EMR), and even endoscopic submucosal dissection (ESD). The occurrence of CS after polypectomy or EMR varies according previous reports; most report an occurrence rate around 1%. However, artificial ulcers after ESD are largely theoretical, and CS following ESD was reported in about 9% of cases, which is higher than that for CS after polypectomy or EMR. Most cases of post-polypectomy syndrome (PPS) have an excellent prognosis, and they are managed conservatively with medical therapy. PPS rarely develops into delayed perforation. Delayed perforation is a severe adverse event that often requires emergency surgery. Since few studies have reported on CS and delayed perforation associated with CS, we focused on CS after colonoscopic treatments in this review. Clinicians should consider delayed perforation in CS patients.

Higher serum uric acid levels and advanced age are associated with an increased prevalence of colorectal polyps

The present study retrospectively analyzed the laboratory data of patients who had undergone a colonoscopy between April 2011 and March 2014, with the aim of assessing whether these variables could be used to predict the presence of colorectal polyps (CP). A total of 1,471 patients were enrolled (731 men, 68.5±10.8 years; 740 women, 66.7±10.8 years). One-way analysis of variance was performed to analyze the association between the presence of CP and a range of laboratory variables. Logistic regression analysis was performed to establish a regression equation to predict the presence of CP. Receiver-operator characteristics analysis was applied to investigate the performance of the regression equation. Patients with CP were older than those without CP (P<0.0001). Serum uric acid (UA) levels were higher in patients with CP, compared to those without CP (P=0.0007). To investigate the possibility that older age and higher UA levels could predict the presence of CP, logistic regression analysis was performed (P=0.0008). The regression equation was as follows: ln(p/1 - p) = 2.79015 - 0.01836 × age - 0.28542 × UA (mg/dl), where p indicates the presence of CP. Receiver-operator characteristic analysis showed the area under the curve to be 0.62092 and the threshold value of P was 0.4370. Sensitivity and specificity of the threshold value were 77.6 and 44.2%, respectively. Advanced age and higher serum UA levels were associated with the presence of CP. In conclusion, logistic regression analysis obtained a regression equation that predicted the presence of CP with a higher sensitivity, but poorer specificity, compared to fecal occult blood testing.

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.

What is the most accurate method for the treatment of diminutive colonic polyps?: Standard versus jumbo forceps polypectomy

Different methods such as standard, hot, and jumbo forceps are used in endoscopic treatment of diminutive colon polyps. In the current study, it was aimed to compare efficacy and safety of standard and jumbo forceps polypectomy methods in treatment of diminutive colon polyps of ≤5 mm. Polyps with ≤5 mm which were excised during colonoscopy by using standard or jumbo forceps were evaluated. Standard and jumbo forceps polypectomy methods were randomly performed in 212 consecutive patients with diminutive colorectal polyp. One-bite polypectomy and complete resection rates were also determined among polypectomy methods. Results of 161 standard forceps polypectomy and 102 jumbo forceps polypectomy were retrospectively evaluated. Both one-bite polypectomy and complete resection rates were significantly higher in the jumbo forceps polypectomy group than the standard forceps polypectomy group (P < 0.001). In the subgroup analysis performed according to polyp sizes, complete resection rate among polyps with 3-mm diameter was determined as 100%. However, numbers of bites in 4-mm and 5-mm polyps were higher in the standard forceps polypectomy group, and complete resection rate was lower than in the jumbo forceps polypectomy group (P < 0.001). Both endoscopic treatment methods may be employed in treatment of diminutive colon polyps with ≤5 mm. However, jumbo forceps polypectomy is a more effective treatment method in 4- to 5-mm polyps with high one-bite polypectomy and complete resection rate.