Risk factors for incomplete polyp resection during colonoscopic polypectomy

Emerge of colorectal cancer in Lynch syndrome despite colonoscopy surveillance: A challenge of hide and seek

Even with colonoscopy surveillance, Lynch syndromes (LS) carriers still develop colorectal cancer (CRC). The cumulative incidence of CRCs under colonoscopy surveillance varies depending on the affected mismatch repair (MMR) gene. However, the precise mechanisms driving these epidemiological patterns remain incompletely understood. In recent years, several potential mechanisms explaining the occurrence of CRCs during colonoscopy surveillance have been proposed in individuals with and without LS. These encompass biological factors like concealed/accelerated carcinogenesis through a bypassed adenoma stage and accelerated progression from adenomas. Alongside these, various colonoscopy-related factors may contribute to formation of CRCs under colonoscopy surveillance, like missed yet detectable (pre)cancerous lesions, detected yet incompletely removed (pre)cancerous lesions, and colonoscopy-induced carcinogenesis due to tumor cell reimplantation. In this comprehensive literature update, we reviewed these potential factors and evaluated their relevance to each MMR group in an attempt to raise further awareness and stimulate research regarding this conflicting phenomenon.

Interval Colorectal Cancer in Inflammatory Bowel Disease: A Review

Inflammatory bowel disease (IBD) increases the risk of dysplasia and colorectal cancer (CRC). Moreover, colitis-associated CRC is responsible for a disproportionate number of CRC-related mortality. For this reason, societies recommend screening and surveillance colonoscopy as the standard of care for patients with ulcerative colitis and Crohn's colitis. Nonetheless, interval cancer defined as CRC detected within the appropriate surveillance interval might still occur despite following guideline recommendations. Even though there is limited data on risk factors associated with interval CRC in IBD, patient and disease-associated factors and technical aspects of the surveillance might play a role. This review aims to provide information on the epidemiology of interval CRC in IBD, the factors that might be associated with its occurrence, and the challenges of CRC screening and dysplasia management in patients with IBD.

Outcomes of thin versus thick-wire snares for cold snare polypectomy: a systematic review and meta-analysis

BACKGROUND/AIMS

Cold snare polypectomy (CSP) is commonly used for the resection of colorectal polyps ≤10 mm. Data regarding the influence of snare type on CSP effectiveness are conflicting. Hence, this meta-analysis aimed to compare the outcomes and safety of thin- and thick-wire snares for CSP.

METHODS

A comprehensive search of the literature published between 2000 and 2021 was performed of various databases for comparative studies evaluating the outcomes of thin- versus thick-wire snares for CSP.

RESULTS

Five studies with data on 1,425 polyps were included in the analysis. The thick-wire snare was comparable to the thin-wire snare with respect to complete histological resection (risk ratio [RR], 1.03; 95% confidence interval [CI], 0.97-1.09), overall bleeding (RR, 0.98; 95% CI, 0.40-2.40), polyp retrieval (RR, 1.01; 95% CI, 0.97-1.04), and involvement of submucosa in the resection specimen (RR, 1.28; 95% CI, 0.72-2.28). There was no publication bias and a small study effect, and the relative effects remained the same in the sensitivity analysis.

CONCLUSION

CSP using a thin-wire snare has no additional benefit over thick-wire snares in small colorectal polyps. Factors other than snare design may play a role in improving CSP outcomes.

Colonoscopy surveillance following adenoma removal to reduce the risk of colorectal cancer: a retrospective cohort study

BACKGROUND

Colonoscopy surveillance is recommended for some patients post polypectomy. The 2002 UK surveillance guidelines classify post-polypectomy patients into low, intermediate and high risk, and recommend different strategies for each classification. Limited evidence supports these guidelines.

OBJECTIVES

To examine, for each risk group, long-term colorectal cancer incidence by baseline characteristics and the number of surveillance visits; the effects of interval length on detection rates of advanced adenomas and colorectal cancer at first surveillance; and the cost-effectiveness of surveillance compared with no surveillance.

DESIGN

A retrospective cohort study and economic evaluation.

SETTING

Seventeen NHS hospitals.

PARTICIPANTS

Patients with a colonoscopy and at least one adenoma at baseline.

MAIN OUTCOME MEASURES

Long-term colorectal cancer incidence after baseline and detection rates of advanced adenomas and colorectal cancer at first surveillance.

DATA SOURCES

Hospital databases, NHS Digital, the Office for National Statistics, National Services Scotland and Public Health England.

METHODS

Cox regression was used to compare colorectal cancer incidence in the presence and absence of surveillance and to identify colorectal cancer risk factors. Risk factors were used to stratify risk groups into higher- and lower-risk subgroups. We examined detection rates of advanced adenomas and colorectal cancer at first surveillance by interval length. Cost-effectiveness of surveillance compared with no surveillance was evaluated in terms of incremental costs per colorectal cancer prevented and per quality-adjusted life-year gained.

RESULTS

Our study included 28,972 patients, of whom 14,401 (50%), 11,852 (41%) and 2719 (9%) were classed as low, intermediate and high risk, respectively. The median follow-up time was 9.3 years. Colorectal cancer incidence was 140, 221 and 366 per 100,000 person-years among low-, intermediate- and high-risk patients, respectively. Attendance at one surveillance visit was associated with reduced colorectal cancer incidence among low-, intermediate- and high-risk patients [hazard ratios were 0.56 (95% confidence interval 0.39 to 0.80), 0.59 (95% confidence interval 0.43 to 0.81) and 0.49 (95% confidence interval 0.29 to 0.82), respectively]. Compared with the general population, colorectal cancer incidence without surveillance was similar among low-risk patients and higher among high-risk patients [standardised incidence ratios were 0.86 (95% confidence interval 0.73 to 1.02) and 1.91 (95% confidence interval 1.39 to 2.56), respectively]. For intermediate-risk patients, standardised incidence ratios differed for the lower- (0.70, 95% confidence interval 0.48 to 0.99) and higher-risk (1.46, 95% confidence interval 1.19 to 1.78) subgroups. In each risk group, incremental costs per colorectal cancer prevented and per quality-adjusted life-year gained with surveillance were lower for the higher-risk subgroup than for the lower-risk subgroup. Incremental costs per quality-adjusted life-year gained were lowest for the higher-risk subgroup of high-risk patients at £7821.

LIMITATIONS

The observational design means that we cannot assume that surveillance caused the reductions in cancer incidence. The fact that some cancer staging data were missing places uncertainty on our cost-effectiveness estimates.

CONCLUSIONS

Surveillance was associated with reduced colorectal cancer incidence in all risk groups. However, in low-risk patients and the lower-risk subgroup of intermediate-risk patients, colorectal cancer incidence was no higher than in the general population without surveillance, indicating that surveillance might not be necessary. Surveillance was most cost-effective for the higher-risk subgroup of high-risk patients.

FUTURE WORK

Studies should examine the clinical effectiveness and cost-effectiveness of post-polypectomy surveillance without prior classification of patients into risk groups.

TRIAL REGISTRATION

This trial is registered as ISRCTN15213649.

FUNDING

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 26. See the NIHR Journals Library website for further project information.

Colorectal cancer risk following polypectomy in a multicentre, retrospective, cohort study: an evaluation of the 2020 UK post-polypectomy surveillance guidelines

OBJECTIVE

Colonoscopy surveillance aims to reduce colorectal cancer (CRC) incidence after polypectomy. The 2020 UK guidelines recommend surveillance at 3 years for 'high-risk' patients with ≥2 premalignant polyps (PMPs), of which ≥1 is 'advanced' (serrated polyp (or adenoma) ≥10 mm or with (high-grade) dysplasia); ≥5 PMPs; or ≥1 non-pedunculated polyp ≥20 mm; 'low-risk' patients without these findings are instead encouraged to participate in population-based CRC screening. We examined the appropriateness of these risk classification criteria and recommendations.

DESIGN

Retrospective analysis of patients who underwent colonoscopy and polypectomy mostly between 2000 and 2010 at 17 UK hospitals, followed-up through 2017. We examined CRC incidence by baseline characteristics, risk group and number of surveillance visits using Cox regression, and compared incidence with that in the general population using standardised incidence ratios (SIRs).

RESULTS

Among 21 318 patients, 368 CRCs occurred during follow-up (median: 10.1 years). Baseline CRC risk factors included age ≥55 years, ≥2 PMPs, adenomas with tubulovillous/villous/unknown histology or high-grade dysplasia, proximal polyps and a baseline visit spanning 2-90 days. Compared with the general population, CRC incidence without surveillance was higher among those with adenomas with high-grade dysplasia (SIR 1.74, 95% CI 1.21 to 2.42) or ≥2 PMPs, of which ≥1 was advanced (1.39, 1.09 to 1.75). For low-risk (71%) and high-risk (29%) patients, SIRs without surveillance were 0.75 (95% CI 0.63 to 0.88) and 1.30 (1.03 to 1.62), respectively; for high-risk patients after first surveillance, the SIR was 1.22 (0.91 to 1.60).

CONCLUSION

These guidelines accurately classify post-polypectomy patients into those at high risk, for whom one surveillance colonoscopy appears appropriate, and those at low risk who can be managed by non-invasive screening.

Endoscopic resection outcomes and predictors of failed en bloc endoscopic mucosal resection of colorectal polyps ≤ 20 mm among advanced endoscopy trainees

Background and study aims  En bloc endoscopic mucosal resection (EMR) is preferred over piecemeal resection for polyps ≤ 20 mm. Data on colorectal EMR training are limited. We aimed to evaluate the en bloc EMR rate of polyps ≤ 20 mm among advanced endoscopy trainees and to identify predictors of failed en bloc EMR. Methods  This was a multicenter prospective study evaluating trainee performance in EMR during advanced endoscopy fellowship. A logistic regression model was used to identify the number of procedures and lesion cut-off size associated with an en bloc EMR rate of ≥ 80 %. Multivariate analysis was performed to identify predictors of failed en bloc EMR. Results  Six trainees from six centers performed 189 colorectal EMRs, of which 104 (55 %) were for polyps ≤ 20 mm. Of these, 57.7 % (60/104) were resected en bloc. Trainees with ≥ 30 EMRs (OR 6.80; 95 % CI: 2.80-16.50; P  = 0.00001) and lesions ≤ 17 mm (OR 4.56;95 CI:1.23-16.88; P  = 0.02) were more likely to be associated with an en bloc EMR rate of ≥ 80 %. Independent predictors of failed en bloc EMR on multivariate analysis included: larger polyp size (OR:6.83;95 % CI:2.55-18.4; P  = 0.0001), right colon location (OR:7.15; 95 % CI:1.31-38.9; P  = 0.02), increased procedural difficulty (OR 2.99; 95 % CI:1.13-7.91; P  = 0.03), and having performed < 30 EMRs (OR: 4.87; 95 %CI: 1.05-22.61; P  = 0.04). Conclusions  In this pilot study, we demonstrated that a relatively low proportion of trainees achieved en bloc EMR for polyps ≤ 20 mm and identified procedure volume and lesion size thresholds for successful en bloc EMR and independent predictors for failed en bloc resection. These preliminary results support the need for future efforts to define EMR procedure competence thresholds during training.

Incomplete endoscopic resection of colorectal polyps: a prospective quality assurance study

BACKGROUND

 Endoscopic screening with polypectomy has been shown to reduce colorectal cancer incidence in randomized trials. Incomplete polyp removal and subsequent development of post-colonoscopy cancers may attenuate the effect of screening. This study aimed to quantify the extent of incomplete polyp removal.

METHODS

 We included patients aged 50-75 years with nonpedunculated polyps ≥ 5 mm removed during colonoscopy at four hospitals in Norway. To evaluate completeness of polyp removal, biopsies from the resection margins were obtained after polypectomy. Logistic regression models were fitted to identify factors explaining incomplete resection.

RESULTS

 246 patients with 339 polyps underwent polypectomy between January 2015 and June 2017. A total of 12 polyps were excluded due to biopsy electrocautery damage, and 327 polyps in 246 patients (mean age 67 years [range 42-83]; 52 % male) were included in the analysis. Overall, 54 polyps (15.9 %) in 54 patients were incompletely resected. Histological diagnosis of the polyp (sessile serrated lesions vs. adenoma, odds ratio [OR] 10.9, 95 % confidence interval [CI] 3.9-30.1) and polyp location (proximal vs. distal colon, OR 2.8, 95 %CI 1.0-7.7) were independent risk factors for incomplete removal of polyps 5-19 mm. Board-certified endoscopists were not associated with lower rates of incomplete resection compared with trainees (14.0 % vs. 14.2 %), OR 1.0 (95 %CI 0.5-2.1).

CONCLUSION

Incomplete polyp resection was frequent after polypectomy in routine clinical practice. Serrated histology and proximal location were independent risk factors for incomplete resection. The performance of board-certified gastroenterologists was not superior to that of trainees.

Quality indicators for screening colonoscopy and colonoscopist performance and the subsequent risk of interval colorectal cancer: a systematic review

OBJECTIVE

The objective of this review was to assess the association between quality indicators used to evaluate individual colonoscopist performance and subsequent interval colorectal cancers (CRCs) in patients participating in bowel cancer screening programs.

INTRODUCTION

Colorectal cancer is a leading cause of cancer death. Bowel cancer screening has been shown to reduce CRC mortality and morbidity, and has therefore been introduced in many countries. Endoscopy societies have developed quality assurance guidelines and guidelines on quality indicators for screening colonoscopies. These quality indicators need to be validated against a relevant outcome to assess their value.

INCLUSION CRITERIA

We included studies on screening colonoscopies conducted on participants in a bowel cancer screening program, regardless of comorbidity. Studies on procedures performed on patients with known CRC, hereditary nonpolyposis colorectal cancer or familial adenomatous polyposis were excluded. We also included studies evaluating the quality indicators of withdrawal time (WT), cecal intubation rate (CIR) and adenoma detection rate (ADR). The search did not reveal any studies evaluating the quality indicators polyp retrieval rate and incomplete adenoma resection/incomplete polyp resection. Only studies with interval CRC as an outcome were included (i.e. CRC diagnosed after a negative screening colonoscopy, but before the next recommended examination date).

METHODS

Published studies were searched in: MEDLINE, Embase, Web of Science and CINAHL. Unpublished studies were searched in: OpenGrey and Grey Literature Report. The sources were searched from 1980 to2018. Data were extracted using the JBI critical appraisal checklist for analytical cross sectional studies. A meta-analysis was conducted based on three of the colonoscopist dependent quality indicators: WT, CIR and ADR.

RESULTS

Seven prospective and retrospective cohort studies were included out of 2373 papers identified after duplicates were removed. The included studies were on bowel cancer screening programs with colonoscopy as the primary screening tool, resulting in the inclusion of a total of 616,390 screening colonoscopies performed by 1431 colonoscopists and 2319 subsequent interval CRCs. Six studies were assessed as high-quality studies, and one study was of low quality. The meta-analysis on WT revealed a 61% lower risk of interval CRC among the patients if the mean WT per colonoscopist was >6 minutes as compared to a mean WT of <6 minutes (RR: 0.39 [95% CI: 0.23 - 0.66]). The meta-analysis on CIR revealed a 31% lower risk of interval CRC among the patients if the CIR per colonoscopist was ≥90% as compared to a CIR of <85% (RR: 0.69 [95% CI: 0.56 - 0.83]). One of two meta-analyses on the individual colonoscopist ADR suggested that this should be 15-19%, as compared to an ADR <10% (RR: 0.77 [95% CI: 0.62 - 0.96]), in order to significantly reduce the risk of interval CRC. The other meta-analysis on ADR revealed a significant association between an individual colonoscopist ADR of ≥25% and a lower risk of interval CRC as compared to an ADR of <25% (RR: 0.51 [95% CI: 0.33 - 0.80]). The meta-analyses on WT and CIR showed no heterogeneity concerning the significant results (I = 0.0%). A high variability across studies due to heterogeneity concerning an ADR of ≥20% resulted in an I = 59.9%, and an I = 63.2% for an ADR of ≥25%.

CONCLUSIONS

To minimize the risk of interval CRC, it may be recommended that WT and CIRs are monitored in bowel cancer screening programs, with an optimal individual colonoscopist mean withdrawal time of >6 minutes and a cecal intubation rate of ≥90%. In bowel cancer screening programs using colonoscopy as their primary screening tool, it may be recommended that the individual colonoscopist ADR be 15-19% or better ≥25% to minimize the risk of interval CRC.

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.

Long-term colorectal cancer incidence after adenoma removal and the effects of surveillance on incidence: a multicentre, retrospective, cohort study

OBJECTIVE

Postpolypectomy colonoscopy surveillance aims to prevent colorectal cancer (CRC). The 2002 UK surveillance guidelines define low-risk, intermediate-risk and high-risk groups, recommending different strategies for each. Evidence supporting the guidelines is limited. We examined CRC incidence and effects of surveillance on incidence among each risk group.

DESIGN

Retrospective study of 33 011 patients who underwent colonoscopy with adenoma removal at 17 UK hospitals, mostly (87%) from 2000 to 2010. Patients were followed up through 2016. Cox regression with time-varying covariates was used to estimate effects of surveillance on CRC incidence adjusted for patient, procedural and polyp characteristics. Standardised incidence ratios (SIRs) compared incidence with that in the general population.

RESULTS

After exclusions, 28 972 patients were available for analysis; 14 401 (50%) were classed as low-risk, 11 852 (41%) as intermediate-risk and 2719 (9%) as high-risk. Median follow-up was 9.3 years. In the low-risk, intermediate-risk and high-risk groups, CRC incidence per 100 000 person-years was 140 (95% CI 122 to 162), 221 (195 to 251) and 366 (295 to 453), respectively. CRC incidence was 40%-50% lower with a single surveillance visit than with none: hazard ratios (HRs) were 0.56 (95% CI 0.39 to 0.80), 0.59 (0.43 to 0.81) and 0.49 (0.29 to 0.82) in the low-risk, intermediate-risk and high-risk groups, respectively. Compared with the general population, CRC incidence without surveillance was similar among low-risk (SIR 0.86, 95% CI 0.73 to 1.02) and intermediate-risk (1.16, 0.97 to 1.37) patients, but higher among high-risk patients (1.91, 1.39 to 2.56).

CONCLUSION

Postpolypectomy surveillance reduces CRC risk. However, even without surveillance, CRC risk in some low-risk and intermediate-risk patients is no higher than in the general population. These patients could be managed by screening rather than surveillance.

Long-term outcomes of endoscopically resected laterally spreading tumors with a positive histological lateral margin

BACKGROUND

With advances in diagnostic endoscopy, the incidence of superficial colorectal tumors, including laterally spreading tumors (LSTs), has increased. However, little is known about the long-term results of LSTs with positive lateral margin after endoscopic treatment. This study aimed to evaluate the long-term clinical outcomes and risk factors for local recurrence of LSTs with positive lateral margin after initial endoscopic resection.

METHODS

We performed a retrospective analysis of the medical records of 324 patients who had 363 LSTs with positive lateral margin after endoscopic resection at a tertiary academic medical center. The medical records from 2011 to 2015 were analyzed. Local recurrence was confirmed through endoscopic finding and subsequent biopsy analysis. We assessed the local recurrence rate and performed multivariate analyses to identify the factors associated with local recurrence.

RESULTS

Follow-up colonoscopy was performed in 176 of 363 LSTs. The local recurrence rate was 6.3% (11/176), with a median (interquartile range [IQR]) follow-up period of 19.8 (12.4-46.5) months. In multivariate analysis, local recurrence was associated with piecemeal resection (odds ratio [OR] 6.62, 95% confidence interval [CI] 1.28-34.33; p = 0.024) and inversely associated with thermal ablation (OR 0.033, 95% CI 0.00-0.45; p = 0.011). At surveillance colonoscopy, histology of the recurrent tumor was adenoma in 10 (90.9%) of 11; these were treated endoscopically.

CONCLUSIONS

In this retrospective study, we found that endoscopically resected LSTs with positive lateral margin have a low recurrence rate. Piecemeal resection was associated with higher local recurrence, and thermal ablation was inversely associated with local recurrence. Endoscopic resection with positive lateral margin combined with thermal ablation leads to a low recurrence rate.

Resection rates and safety profile of cold vs. hot snare polypectomy in polyps sized 5-10 mm and 11-20 mm

BACKGROUND AND AIMS

Hot snare (HS) is widely used for the resection of adenomas >5 mm. The cold snare (CS) has a better safety profile and is more cost-effective. The aims of this study were to evaluate effectiveness and safety of CS polypectomy (CSP) compared to HS polypectomy (HSP) for adenomas sized 5-10 mm and 11-20 mm.

METHODS

4018 colonoscopies performed within "quality certificate for screening colonoscopy" with one polypectomy of an adenoma sized 5-20 mm each were included. Retrieval rates, complete resection rates and complication rates were assessed and compared between CSP and HSP for adenomas sized 5-10 mm and 11-20 mm. Histologic subgroups were additionally assessed.

RESULTS

Complete resection rates (5-10 mm: CSP: 89.4% vs. HSP: 87.9%, p = 0.33; 11-20 mm: CSP: 81.8% vs. 80.9%; p = 1), retrieval rates (5-10 mm: CSP: 99.5% vs. HSP: 99.4%, p = 0.76; 11-20 mm: CSP: 100% vs. HSP: 99%, p = 1) and complication rates (5-10 mm: CSP: 0.2% vs. HSP: 0.2%; p = 1; 11-20 mm: CSP: 0% vs. HSP: 1%, p = 1) were equal between CSP and HSP for adenomas sized 5-10 mm as well as 11-20 mm. For serrated adenomas sized 5-10 mm, HSP was superior to CSP (88.7% vs. 77.2%, p < 0.05) regarding the complete resection rate, but not for advanced adenomas (HSP: 89.1% vs. 87.3%, p = 0.69) or adenomas with high-grade dysplasia (HSP: 76.7% vs. 75%, p = 1).

CONCLUSION

This study further supports the use of CSP for polyps sized 5-10 mm and additionally suggests also using CSP for polyps sized 11-20 mm. These findings, as well as the best method for resection of serrated polyps should be validated in further studies.

Investigation of the Local Recurrence Rate after Colorectal Endoscopic Mucosal Resection: Is Incomplete Polyp Resection Really a Clinically Important Problem? Analysis of the Rationale for the "Resect and Discard" Strategy

BACKGROUND/AIMS

The "Resect and Discard" strategy is a potentially useful strategy. At present, only the lesion size and accuracy of diagnosis are cited as considerations for clinical adoption of this strategy. On the other hand, histopathology of the resected specimens after Endoscopic Mucosal Resection (EMR) reveals often an unclear or positive-margin status, implying Incomplete Polyp Resection (IPR). If IPR indeed increased the risk of local recurrence, histopathological evaluation of the margin would be indispensable and clinical adoption of this strategy is difficult. The aim of this study is to verify the association between IPR and the risk of local recurrence.

METHODS

The 1872 polyps and 603 EMR cases in 597 patients who had EMR between May 2013 and May 2014 were enrolled. The local recurrence rate until 3 years after the EMR in cases with the target lesions of the "Resect and Discard" strategy was determined in the negative-margin and IPR groups.

RESULTS

The final analysis was performed using the data of 1092 polyps, and 222 were categorized into the IPR group. There were no cases of recurrence in either of the groups.

CONCLUSION

This is the world's first report conducted to examine the correlation of IPR and the local recurrence rate for clinical practice of "Resect and Discard" strategy. There is the possibility that pathological evaluation of the margins after EMR in patients with small polyps can be skipped.

Technical Feasibility of a Guidetube for Various Endoscopic Procedures in Human Gastrointestinal Simulators

BACKGROUND/AIMS

Many gastrointestinal (GI) endoscopic procedures are difficult and cumbersome owing to the limitation of currently available endoscopic devices. This study aimed to develop an endoscopic guidetube for multipurpose endoscopic procedures and assess its use in a realistic GI endoscopic simulator.

METHODS

The guidetube used is a soft overtube composed of neoprene and is designed to assist various endoscopic procedures on demand. In total, 15 types of procedures were performed in GI simulators. Four procedures were performed in the stomach model and 11 in the colon model. The procedures include repeated endoscopic insertion and foreign body removal in various positions. The mean insertion and procedure time were assessed in each session. All procedures were performed by 5 expert endoscopists.

RESULTS

Endoscopic procedures with the new guidetube were faster and more effective than the conventional endoscopic techniques. The mean insertion time of the endoscope with the guidetube was significantly shorter than that without the guidetube. The guidetube was safely inserted without scratch using low pushing force. Objects of various sizes larger than the endoscopic channel were easily removed by the guidetube-assisted endoscopic procedures.

CONCLUSION

This preliminary study shows that guidetube-assisted endoscopic procedures are faster, easier, safer and cheaper than conventional endoscopic procedures.

Colorectal polyps located across a fold are difficult to resect completely using endoscopic mucosal resection: A propensity score analysis

Background

Incomplete polyp resection during colorectal endoscopic mucosal resection (EMR) might contribute to the development of interval cancer.

Objective

This retrospective study aimed to determine the incidence of incomplete polyp resection during EMR of colorectal polyps located across a fold compared with that of colorectal polyps located between folds.

Methods

In total, 262 patients with 262 lesions that were ≥10 mm in diameter and treated with conventional EMR were enrolled. The main outcome was the incidence of incomplete polyp resections. Propensity score matching and inverse probability of treatment weighting (IPTW) were performed to reduce the effects of selection bias.

Results

Fifty-seven lesions (21.8%) were incompletely resected. After propensity score matching, the lesions located across a fold were at higher risk of incomplete resection than those between folds (26/68, 38.2% vs 7/68, 10.3%; odds ratio (OR): 3.71; 95% confidence interval (CI): 1.61-8.56; p < 0.01). These findings persisted after adjusting for the differences at baseline using the IPTW method (OR: 3.63; 95% CI: 1.72-7.63; p = 0.001).

Conclusions

There is an increased risk of an incomplete polyp resection for a colorectal polyp that is located across a fold compared with that for a polyp that is located between folds.

Quality indicators for screening colonoscopies and colonoscopist performance and the subsequent risk of interval bowel cancer: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this systematic review is to assess the association between quality indicators related to the individual colonoscopist's performance and subsequent interval cancers in patients participating in bowel cancer screening programs, following the JBI approach.This systematic review of association will search all relevant literature on the subject to answer the following review questions.

Clinical Effectiveness of Submucosal Injection with Indigo Carmine Mixed Solution for Colon Endoscopic Mucosal Resection

BACKGROUND/AIMS

Submucosal injection with indigo carmine mixed solution can improve the delineation of colorectal neoplasia during endoscopic mucosal resection (EMR). Thus, the aim of this study was to evaluate the efficacy of submucosal injection with indigo carmine mixed solution during EMR of colorectal neoplasia.

METHODS

This was a prospective, randomized, controlled study of a total of 212 neoplastic colon polyps (5-20 mm) subjected to EMR in a single tertiary university hospital. The patients were randomized into two groups according to whether or not indigo carmine mixed solution was used, and the complete resection rate (CRR) after EMR was evaluated.

RESULTS

A total of 212 neoplastic polyps (normal saline group, 115; indigo carmine group, 97) were successfully removed by EMR. There was no significant difference in the CRR (92.8 vs. 89.6%, p = 0.414) or macroscopic delineation (86.0 vs. 93.8%, p = 0.118) between the two groups. In a separate analysis of sessile serrated adenomas/polyps (SSAs/Ps), macroscopic delineation was better in the indigo carmine group than the normal saline group (87.5 vs. 53.8%), albeit not significantly (p = 0.103). In univariate analyses, the CRR was significantly related to polyp location, polyp morphology, macroscopic delineation, and pathologic findings. In a multiple logistic regression analysis, macroscopic delineation (odds ratio (OR), 7.616, p = 0.001) and polyp pathology (OR, 8.621; p < 0.001) were significantly associated with the CRR.

CONCLUSIONS

Submucosal injection with indigo carmine mixed solution did not improve the CRR or macroscopic delineation of EMR of colorectal neoplasias.

Endoscopic and Clinical Factors Affecting the Prognosis of Colorectal Endoscopic Submucosal Dissection-Related Perforation

Background/Aims

Although colorectal endoscopic submucosal dissection (ESD)-related perforation is not uncommon, the factors affecting clinical outcomes after perforation have not been investigated. This study was designed to investigate the factors influencing the clinical course of ESD-related colon perforation.

Methods

Forty-three patients with colorectal ESD-related perforation were evaluated. The perforations were classified as endoscopic or radiologic perforations. The patients’ medical records and endoscopic pictures were analyzed.

Results

The clinical outcomes were assessed by the duration of nil per os, intravenous antibiotics administration, and hospital stays, which were 2.7±1.5, 4.9±2.3, and 5.1±2.3 days, respectively. Multivariate analyses revealed that a larger tumor size, ESD failure, specific endoscopists, and abdominal pain were independently related to a poorer outcome. The time between perforation and clipping was 15.8±25.4 minutes in the endoscopic perforation group. The multivariate analysis of this group indicated that delayed clipping, specific endoscopists, and abdominal pain were independently associated with poorer outcomes.

Conclusions

Tumor size, ESD failure, abdominal pain, and the endoscopist were factors that affected the clinical outcomes of patients with colorectal ESD-related perforation. The time between the perforation and clipping was an additional factor influencing the clinical course of endoscopic perforation. Decreasing this time period may improve outcomes.