Resection depth and layer of cold snare polypectomy versus endoscopic mucosal resection

Endoscopic Mucosal Resection and Endoscopic Submucosal Dissection

Up to 15% of colorectal polyps are amenable for conventional polypectomy. Advanced endoscopic resection techniques are introduced for the treatment of those polyps. They provide higher en bloc resection rates compared with conventional techniques, while helping patients to avoid the complications of surgery. Note that 20 mm is considered as the largest size of a polyp that can be resected by polypectomy or endoscopic mucosal resection (EMR) in an en bloc fashion. Endoscopic submucosal dissection (ESD) is recommended for polyps larger than 20 mm. Intramucosal carcinomas and carcinomas with limited submucosal invasion can also be resected with ESD. EMR is snare resection of a polyp following submucosal injection and elevation. ESD involves several steps such as marking, submucosal injection, incision, and dissection. Bleeding and perforation are the most common complications following advanced endoscopic procedures, which can be treated with coagulation and endoscopic clipping. En bloc resection rates range from 44.5 to 63% for EMR and from 87.9 to 96% for ESD. Recurrence rates following EMR and ESD are 7.4 to 17% and 0.9 to 2%, respectively. ESD is considered enough for the treatment of invasive carcinomas in the presence of submucosal invasion less than 1000 μm, absence of lymphovascular invasion, well-moderate histological differentiation, low-grade tumor budding, and negative resection margins.

Histopathologic vertical margin positivity in cold snare polypectomy and mucosal resection for sessile serrated lesions

BACKGROUND AND AIMS

Data regarding the status of the vertical margin of sessile serrated lesions (SSLs) resected using cold snare polypectomy (CSP) are lacking, and whether a histopathologically positive vertical margin is related to recurrence remains unclear. Therefore, this preliminary study aimed to clarify the rates of positive or unassessable vertical and horizontal margins and the rate of muscularis mucosae resection in SSLs treated using CSP compared with those treated with EMR.

METHODS

Histologic outcomes of patients treated with CSP or EMR for SSLs were evaluated in this single-center observational study. The primary outcome was the incidence of histopathologically positive vertical margins in CSP and EMR. Furthermore, the comparisons were adjusted for confounding factors using propensity score matching.

RESULTS

Overall, 82 patients with SSLs were included in the CSP and EMR groups after matching. The incidence of positive histologic vertical margins in the CSP and EMR groups were 67.1% and 2.4%, respectively (P < .001). Regarding the evaluation of the presence of muscularis mucosae, 29.3% and 98.8% of patients in the CSP and EMR groups, respectively, had a complete muscularis mucosae resection (P < .001).

CONCLUSIONS

A rigorous histopathologic evaluation revealed that for SSLs, CSP more frequently leads to positive vertical margins than EMR. (Clinical trial registration number: UMIN 000051569.).

Endoscopic techniques for management of large colorectal polyps, strictures and leaks

The implementation of screening colonoscopy with polyp removal has significantly decreased mortality rates associated with colorectal cancer (CRC), although it remains a major cause of cancer-related deaths globally. CRC typically originates from adenomatous polyps, and increased removal of these growths has led to reduced CRC incidence and mortality. Endoscopic polypectomy techniques, including hot and cold snare polypectomy, play a pivotal role in this process. While both methods are effective for small polyps (<10 mm), recent evidence favors cold snare polypectomy due to its superior safety profile and comparable complete resection rates. Large polyps (>10 mm), particularly those with advanced features, pose increased cancer risks and often require meticulous assessment and advanced endoscopic techniques, including endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), for resection. This chapter also provides a practical overview of endoscopic techniques for managing colonic obstructions and pericolonic fluid collections, detailing their indications, advantages, disadvantages, and complications. The goal is to improve understanding and application in clinical practice. Additionally, we provide a summary of endoscopic closure techniques that have revolutionized the management of perforations and fistulas, offering safe and effective alternatives to surgery.

Colorectal Post-polypectomy Bleeding in Outpatient versus Inpatient Treatment: Propensity Score Matching Analysis

Objectives

Delayed bleeding is the most frequent adverse event associated with endoscopic mucosal resection (EMR) and hot snare polypectomy (HSP) of colorectal polyps. However, whether the incidence of delayed bleeding differs between outpatient and inpatient treatment is unknown. Therefore, in this study, we aimed to evaluate delayed bleeding rates between outpatient and inpatient endoscopic treatments and clarify the safety of outpatient treatment.

Methods

We enrolled 469 patients (1077 polyps) and 420 patients (1080 polyps) in the outpatient and inpatient groups, respectively, who underwent EMR or HSP for colorectal polyps at our institution between April 2020 and May 2023. Using propensity score matching, we evaluated the delayed bleeding rates between the two groups. Delayed bleeding was defined as a hemorrhage requiring endoscopic hemostasis occurring within 14 days of the procedure.

Results

Propensity score matching created 376 (954 polyps) matched patient pairs. The median maximum diameter of polyps removed was 10 mm in both groups. Delayed bleeding rates per patients were 1.3% (5/376) in the outpatient group and 2.9% (11/376) in the inpatient group (P=0.21). In term of per polyp, early delayed bleeding (occurring within 24 hours) rates were higher in the inpatient group than outpatient group (0.2% [2/954] vs. 1.1% [10/954], respectively; P=0.04). No severe bleeding requiring a transfusion occurred in either group.

Conclusions

Outpatient endoscopic treatment did not increase delayed bleeding compared with inpatient treatment. Outpatient treatment would be safe and common for the removal of colorectal polyps.

Cold versus hot snare endoscopic mucosal resection for large (≥15 mm) flat non-pedunculated colorectal polyps: a randomised controlled trial

BACKGROUND AND AIMS

Conventional hot snare endoscopic mucosal resection (H-EMR) is effective for the management of large (≥20 mm) non-pedunculated colon polyps (LNPCPs) however, electrocautery-related complications may incur significant morbidity. With a superior safety profile, cold snare EMR (C-EMR) of LNPCPs is an attractive alternative however evidence is lacking. We conducted a randomised trial to compare the efficacy and safety of C-EMR to H-EMR.

METHODS

Flat, 15-50 mm adenomatous LNPCPs were prospectively enrolled and randomly assigned to C-EMR or H-EMR with margin thermal ablation at a single tertiary centre. The primary outcome was endoscopically visible and/or histologically confirmed recurrence at 6 months surveillance colonoscopy. Secondary outcomes were clinically significant post-EMR bleeding (CSPEB), delayed perforation and technical success.

RESULTS

177 LNPCPs in 177 patients were randomised to C-EMR arm (n=87) or H-EMR (n=90). Treatment groups were equivalent for technical success 86/87 (98.9%) C-EMR versus H-EMR 90/90 (100%); p=0.31. Recurrence was significantly greater in C-EMR (16/87, 18.4% vs 1/90, 1.1%; relative risk (RR) 16.6, 95% CI 2.24 to 122; p<0.001).Delayed perforation (1/90 (1.1%) vs 0; p=0.32) only occurred in the H-EMR group. CSPEB was significantly greater in the H-EMR arm (7/90 (7.8%) vs 1/87 (1.1%); RR 6.77, 95% CI 0.85 to 53.9; p=0.034).

CONCLUSION

Compared with H-EMR, C-EMR for flat, adenomatous LNPCPs, demonstrates superior safety with equivalent technical success. However, endoscopic recurrence is significantly greater for cold snare resection and is currently a limitation of the technique.

TRIAL REGISTRATION NUMBER

NCT04138030.

Cold sub-mucosal injection versus traditional cold snare polypectomy for diminutive and small colorectal polyps: A systematic review and meta-analysis

BACKGROUND

The guidelines recommend conventional cold snare polypectomy (C-CSP) for diminutive and small colorectal polyps (≤ 10 mm). However, it remains unclear whether CSP with sub-mucosal injection (SI-CSP) achieves comparable efficacy to C-CSP for managing these lesions. This study compares SI-CSP with C-CSP for patients with diminutive and small colorectal polyps.

METHODS

An electronic literature search was conducted to retrieve articles comparing resection outcomes between SI-CSP and C-CSP in diminutive and small colorectal polyps (registration number INPLASY2023100096). Our primary outcomes of interest were the complete resection rate (CRR), complications (namely immediate bleeding, delayed bleeding and perforation) and polypectomy time. Mean differences with 95% confidence intervals (CI) were employed for continuous variables, while odds ratios (OR) with 95% CI were calculated for categorical variables. Data was analyzed using a random effects model and the I2 test was utilized to assess heterogeneity.

RESULTS

Eight studies involving 1470 patients with 2223 polyps were included in our analysis. The CRR was not significantly higher in the SI-CSP group, with an OR of 95% CI 0.50 (0.22, 1.15). The incidences of immediate bleeding (OR 95% CI 0.60 [0.26-1.40]) and delayed bleeding (OR 95% CI 0.88 [0.32-2.42]) did not differ significantly between the two groups. On average, the mean polypectomy time was 64.75 seconds shorter in the C-CSP group (95% CI, - 102.96 to - 26.53). Notably, no perforation events were reported in the included studies.

CONCLUSIONS

The use of SI-CSP was not superior to C-CSP in managing diminutive and small colorectal polyps and the procedure required significantly more time.

Effect of Cold Versus Hot Snare Polypectomy on Colon Postpolypectomy Bleeding in Patients with End-Stage Renal Disease: A Retrospective Cohort Study

BACKGROUND

Patients with end-stage renal disease (ESRD) who undergo polypectomy may experience postpolypectomy bleeding. To reduce the risk of delayed postpolypectomy bleeding among the general population, cold snare polypectomy (CSP) is recommended for removing colon polyps smaller than 1 cm. Nevertheless, only few studies have examined the effect of CSP on patients with ESRD.

METHODS

We retrospectively analyzed the data of patients with ESRD who underwent colonoscopic polypectomy for polyps larger than 5 mm at a Taiwanese university hospital from January 2014 to January 2023. The main outcome was delayed postpolypectomy bleeding within 30 days. Multivariate analysis was conducted to adjust for major confounders.

RESULTS

A total of 557 patients with ESRD underwent colonoscopic polypectomy during the study period: 201 underwent CSP and 356 underwent hot snare polypectomy (HSP). Delayed postpolypectomy bleeding occurred in 27 patients (4.8%). The rate of delayed postpolypectomy bleeding was lower in patients with ESRD who underwent CSP than in those who underwent HSP (1.9% vs. 6.4%, P = 0.022). The percentage of patients who did not experience postpolypectomy bleeding within 30 days after CSP remained lower than that observed after HSP (P = 0.019, log-rank test). Multivariate analysis demonstrated immediate postpolypectomy bleeding and HSP to be independent risk factors for delayed postpolypectomy bleeding. A nomogram prognostic model was used to predict the potential of delayed postpolypectomy bleeding within 30 days in patients with ESRD.

CONCLUSIONS

Compared with HSP, CSP is more effective in mitigating the risk of delayed postpolypectomy bleeding in patients with ESRD.

Low-power pure-cut hot snare polypectomy for colorectal polyps 10-14 mm in size: a multicenter retrospective study

BACKGROUND AND AIM

Hot snare excision using electrocautery is widely used for large colorectal polyps (>10 mm); however, adverse events occur due to deep thermal injury. Colorectal polyps measuring 10-14 mm rarely include invasive cancer. Therefore, less invasive therapeutic options for this size category are demanding. We have developed hot snare polypectomy with low-power pure-cut current (LPPC HSP), which is expected to contribute to less deep thermal damage and lower risk of adverse events. This study aimed to evaluate the efficacy and safety of LPPC HSP for 10-14 mm colorectal polyps, compared with conventional endoscopic mucosal resection (EMR).

METHODS

In this multicenter, retrospective, observational study, clinical outcomes of EMR and LPPC HSP for 10-14 mm nonpedunculated colorectal polyps between January 2021 and March 2022 were compared using propensity score matching.

RESULTS

We identified 203 EMR and 208 LPPC HSP cases. After propensity score matching, the baseline characteristics between the groups were comparable, with 120 pairs. The en bloc and R0 resection rates were not significantly different between EMR and LPPC HSP groups (95.8% vs 97.5%, P = 0.72; 90.0% vs 91.7%, P = 0.82). The rates of delayed bleeding and perforation did not differ between the groups.

CONCLUSIONS

Compared with conventional EMR, LPPC HSP showed a similar resection ability without an increase in adverse events. These results suggest that LPPC HSP is a safe and effective treatment for 10-14 mm nonpedunculated colorectal polyps.

Safe and effective hybrid endoscopic submucosal dissection with ALL IN ONE snare in porcine gastric model (with video)

This study aimed to evaluate the safety and efficiency of hybrid endoscopic submucosal dissection (H-ESD) using a newly developed ALL IN ONE (AIO) snare. This was a matched control study in a porcine model. Five paired simulated stomach lesions 2-2.5 cm in size were removed by H-ESD using an AIO snare or conventional ESD (C-ESD) using an endoscopic knife. The outcomes of the two procedures were compared, including en-bloc resection rates, procedure times, intraprocedural bleeding volumes, muscular injuries, perforations, thicknesses of the submucosal layer in resected specimens, and stomach defects. All simulated lesions were resected en-bloc. Specimens resected by H-ESD and C-ESD were similar in size (7.68 ± 2.92 vs. 8.42 ± 2.42 cm2; P = 0.676). H-ESD required a significantly shorter procedure time (13.39 ± 3.78 vs. 25.99 ± 4.52 min; P = 0.031) and submucosal dissection time (3.99 ± 1.73 vs. 13.1 ± 4.58 min; P = 0.003) versus C-ESD; H-ESD also yielded a faster dissection speed (241.37 ± 156.84 vs. 68.56 ± 28.53 mm2/min; P = 0.042) and caused fewer intraprocedural bleeding events (0.40 ± 0.55 vs. 3.40 ± 1.95 times/per lesion; P = 0.016) than C-ESD. The thicknesses of the submucosal layer of the resected specimen (1190.98 ± 134.07 vs. 1055.90 ± 151.76 μm; P = 0.174) and the residual submucosal layer of the stomach defect (1607.94 ± 1026.74 vs. 985.98 ± 445.58 μm; P = 0.249) were similar with both procedures. The AIO snare is a safe and effective device for H-ESD and improves the treatment outcomes of gastric lesions by shortening the procedure time.

Factors determining the resection ability of snares in cold snare polypectomy: Construction of an ex vivo model for accurately evaluating resection ability

OBJECTIVES

Cold snare polypectomy (CSP)-dedicated snares (DSs) may have a higher resection ability than conventional snares. However, a model that can accurately and objectively evaluate and compare the resection ability of each snare has yet to be determined, and characteristics of snare parts that increase resection ability remain unknown. Therefore, we elucidated DSs' resection ability and all characteristics of the parts required for acquiring high resection ability.

METHODS

An ex vivo model for evaluating resection ability was generated using human colons obtained from forensic autopsy specimens. The force required to resect a 15 mm wide human colonic mucosa (FRR) was measured using this model; if the FRR is small, the resection ability is high. Next, after measuring the stiffness of each snare part, the correlation between the stiffness and resection ability was analyzed.

RESULTS

The force required to resect using SnareMaster Plus, Micro-Tech Cold Snare, Captivator Cold, Exacto Cold Snare, or Captivator II was 13.6 ± 1.0, 12.5 ± 1.2, 7.4 ± 1.2, 6.5 ± 1.0, and 28.7 ± 3.7 N, respectively. All DSs had significantly lower FRR than the conventional snare (Captivator II) and had higher resection ability (P < 0.001). A negative correlation was found between FRR and sheath or wire spindle stiffness, with correlation coefficients of 0.72 (P = 0.042) or 0.94 (P < 0.001), respectively. Moreover, 1 × 7 type wire rings had significantly higher friction coefficients than 1 × 3 type wire rings (P < 0.002).

CONCLUSION

Sheath and wire spindle stiffness should be increased to increase resection ability; 1 × 7 type wire rings may be suitable for CSP-snare parts.

Cold Snare Polypectomy With or Without Submucosal Injection for Endoscopic Resection of Colorectal Polyps: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND AIMS

The impact of submucosal injection during cold snare polypectomy (CSP) remains uncertain. We conducted an evidence-based comparison of conventional CSP (C-CSP) and CSP with submucosal injection (SI-CSP) for colorectal polyp resection.

METHODS

PubMed, Embase, and the Cochrane Library databases were searched for randomized controlled trials (RCTs) comparing C-CSP with SI-CSP. Major outcomes included the rates of complete resection, en bloc resection, polyp retrieval, and adverse events, as well as the duration of polypectomy. Data were analyzed by using a random-effects model.

RESULTS

A total of seven RCTs were included. Complete resection rates for all polyps (RR 0.98; 95% CI 0.93-1.03), polyps ≤ 10 mm (RR 0.99; 95% CI 0.96-1.02) and polyps > 10 mm (RR 0.92; 95% CI 0.69-1.12) were not substantially different between C-CSP and SI-CSP groups. En bloc resection rate (RR 0.93; 95% CI 0.79-1.09) and polyp retrieval rate (RR 1.00; 95% CI 0.99-1.01) were also not significantly different between the two groups. The SI-CSP group required a prolonged polypectomy time than the C-CSP group (SMD - 0.89; 95% CI -1.29 to -0.49). Adverse events were rare in both groups.

CONCLUSIONS

SI-CSP is not an optimal substitute for CSP in the resection of colorectal polyps, particularly diminutive and small polyps.

A case of delayed perforation after cold snare polypectomy treated conservatively by endoscopic clip closure

We present the case of a 45-year-old man who underwent a screening total colonoscopy and developed delayed perforation after a cold snare polypectomy in the descending colon and sigmoid colon. The patient developed abdominal pain and was referred to our department for further evaluation and treatment. On clinical examination, we noted lower abdominal tenderness, mild rebound pain, and elevated levels of inflammatory markers. Abdominal contrast-enhanced computed tomography confirmed the presence of free air in the abdomen. Since there were no signs of peritoneal inflammation and the vital signs were stable, we planned to perform endoscopic clip closure of the perforated area. The patient's symptoms improved with conservative management thereafter, including fasting, fluid replacement, and antibiotic administration. The patient was discharged on the 6th hospital day. In this case report, we discuss the usefulness of endoscopic clip closure in managing delayed perforation.

One-device colonoscopy: feasibility, cost savings, and plastic waste reduction by procedure indication, when performed by a high detecting colonoscopist

BACKGROUND

Cold forceps and snares are each effective for removing polyps of 1-3 mm, while snares are more effective for polyps of 4-10 mm in size. If, in the same patient, polyps of 1-3 mm are removed with forceps and those of 4-10 mm with snares, two devices are used. If cold snares are used to resect all lesions of 1-10 mm (one-device colonoscopy), there is a potential for lower costs and less plastic waste.

METHODS

A single high detecting colonoscopist prospectively measured the feasibility of cold snaring all colorectal lesions of ≤10 mm in size, along with the associated costs and plastic waste reduction.

RESULTS

677 consecutive lower gastrointestinal endoscopies (not for inflammatory bowel disease) were assessed. Of 1430 lesions of 1-3 mm and 1685 lesions of 4-10 mm in size, 1428 (99.9%, 95%CI 99.5%-100%) and 1674 (99.3%, 95%CI 98.8%-99.7%), respectively, were successfully resected using cold snaring. Among 379 screening and surveillance patients, universal cold snaring of lesions ≤10 mm saved 35 and 47 cold forceps per 100 screening and surveillance patients, respectively.

CONCLUSION

Cold snare resection of all lesions ≤10 mm (one-device colonoscopy) was feasible, and reduced costs and plastic waste.

The efficacy and safety of cold snare polypectomy with submucosal injection for the removal of polyps less than 20 mm in size: a systematic review and meta-analysis

BACKGROUND AND AIM

Neoplastic polyp removal is important for colorectal cancer prevention. Endoscopists have proposed cold snare endoscopic mucosal resection (CS-EMR) as a solution to solve positive cutting edges and postoperative bleeding. However, many controversies regarding its specific performance in practice have been reported. The aim of this pooled analysis was to report the efficacy and safety of CS-EMR.

METHODS

PubMed/Medline, Embase, Google Scholar, and the Cochrane Library searched up to January 2022 to identify studies in which CS-EMR was performed for the removal of colorectal polyps measuring less than 20 mm. The primary outcome was the complete resection rate (CRR), and the secondary outcome was the rate of adverse events.

RESULTS

Eleven studies were included in the final analysis, which included 861 colorectal polyps. The overall CRR with CS-EMR was 96.3% (95% CI, 93.9-98.2%). The early and delayed bleeding rates of CS-EMR were 3.1% (95% CI, 1.2-5.5%) and 1.4% (95% CI, 0.6-2.4%), respectively. There were no statistical significances between CS-EMR and cold snare polypectomy (CSP) in terms of the CRR and adverse events, as well as CS-EMR and hot snare endoscopic mucosal resection (HS-EMR).

CONCLUSIONS

For resecting colorectal polyps measuring ≤20 mm, CS-EMR is an effective attempt. However, compared with CSP and HS-EMR, CS-EMR did not improve the efficiency and safety of polypectomy as expected. Multicenter randomized controlled trials are needed to compare CSP with CS-EMR in the resection of <10 mm polyps and HSP with CS-EMR in the resection of ≥10 mm polyps.

Sessile serrated lesions with dysplasia: is it possible to nip them in the bud?

The serrated neoplasia pathway constitutes an "alternative route" to colorectal cancer (CRC), and sessile serrated lesions with dysplasia (SSLDs) are an intermediate step between sessile serrated lesions (SSLs) and invasive CRC in this pathway. While SSLs show indolent growth before becoming dysplastic (> 10-15 years), SSLDs are considered to rapidly progress to either immunogenic microsatellite instable-high (MSI-H) CRC (presumably 75% of cases) or mesenchymal microsatellite stable (MSS) CRC. Their flat shapes and the relatively short window of this intermediate state make it difficult to detect and diagnose SSLDs; thus, these lesions are potent precursors of post-colonoscopy/interval cancers. Confusing terminology and the lack of longitudinal observation data of serrated polyps have hampered the accumulation of knowledge about SSLDs; however, a growing body of evidence has started to clarify their characteristics and biology. Together with recent efforts to incorporate terminology, histological studies of SSLDs have identified distinct dysplastic patterns and revealed alterations in the tumor microenvironment (TME). Molecular studies at the single-cell level have identified distinct gene alterations in both the epithelium and the TME. Mouse serrated tumor models have demonstrated the importance of TME in disease progression. Advances in colonoscopy provide clues to distinguish pre-malignant from non-malignant-SSLs. Recent progress in all aspects of the field has enhanced our understanding of the biology of SSLDs. The aim of this review article was to assess the current knowledge of SSLDs and highlight their clinical implications.

Cold resection for colorectal polyps: where we are and where we are going?

INTRODUCTION

Endoscopic resection of colonic precancerous lesions has been demonstrated to significantly decrease colorectal cancer (CRC) incidence and mortality. Among resection techniques, cold snare polypectomy (CSP) has been shown as a highly feasible, effective and safe option and is widely used in clinical practice, being regarded as the first-line technique for removal of small and diminutive colorectal polyps. On the other hand, conventional hot snare polypectomy (HSP) and endoscopic mucosal resection (EMR), namely the gold standard treatments for larger polyps, may be occasionally associated to complications due to electrocautery injury.

AREAS COVERED

To overcome these shortcomings of electrocautery-based resection techniques, in the last few years CSP has been increasingly assessed as a treatment option for additional indications, with a focus on nonpedunculated colorectal polyps ≥10 mm.

EXPERT OPINION

This review aims to present current and widened indications of CSP discussing the latest findings from the most remarkable studies, with an insight into technical issues, novelties and potential advances in the near future.

Hot snare polypectomy vs endoscopic mucosal resection using bipolar snare for intermediate size colorectal lesions: Propensity score matching

BACKGROUND

Endoscopic resection (ER) with bipolar snare, in which the electric current only passes through the tissue between the device’s two electrodes, is a prominent method used to prevent perforation due to electricity potentially. ER using bipolar snare with or without submucosal injection enabled safe resection of colorectal lesions measuring 10–15 mm in an ex vivo porcine model. ER with bipolar snare is expected to have good treatment outcomes in 10–15 mm colorectal lesions, with high safety even without submucosal injection. However, no clinical reports have compared treatment outcomes with and without submucosal injection.

AIM

To compare the treatment outcomes of bipolar polypectomy with hot snare polypectomy (HSP) to those with endoscopic mucosal resection (EMR).

METHODS

In this single-centre retrospective study, we enrolled 10–15 mm nonpedunculated colorectal lesions (565 Lesions in 463 patients) diagnosed as type 2A based on the Japan Narrow-band Imaging Expert Team classification, resected by either HSP or EMR between January 2018 and June 2021 at the National Cancer Center Hospital East. Lesions were divided into HSP and EMR groups, and propensity score matching was performed. In the matched cohort, en bloc and R0 resection rates and adverse events were compared between the two groups.

RESULTS

Of the 565 lesions in 463 patients, 117 lesions each in the HSP and EMR groups were selected after propensity score matching. In the original cohort, there was a significant difference in antithrombotic drug use (P < 0.05), lesion size (P < 0.01), location (P < 0.01), and macroscopic type (P < 0.05) between the HSP and EMR groups. In the matched cohort, the en bloc resection rates were comparable between both groups [93.2% (109/117) vs 92.3% (108/117), P = 0.81], and there was no significant difference in the R0 resection rate [77.8% (91/117) vs 80.3% (94/117), P = 0.64]. The incidence of delayed bleeding was similar in both groups [1.7% (2/117)]. Perforation occurred in the EMR group [0.9% (1/117)] but not in the HSP group.

CONCLUSION

Using bipolar snare, ER of nonpedunculated 10–15 mm colorectal lesions may be performed safely and effectively, even without submucosal injection.

The efficacy and safety of cold snare versus hot snare polypectomy for endoscopic removal of small colorectal polyps: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The optimal technique for removing small colorectal polyps ranging from 5 to 10 mm in size remains uncertain. In order to compare the efficacy and adverse events between cold snare polypectomy (CSP) and hot snare polypectomy (HSP) for removing small polyps, we conducted a systematic review and meta-analysis of available randomized controlled trials.

METHODS

We conducted a comprehensive search of MEDLINE, EMBASE, and the Cochrane Library databases from 1998 to May 2023 to identify randomized controlled trials that evaluated the efficacy and safety of cold snare polypectomy (CSP) and hot snare polypectomy (HSP) for resecting small colorectal polyps. The primary outcome measure was the incomplete resection rate (IRR).

RESULTS

Seven studies that met our study criteria, with a total of 3178 included polyps, were included in our analysis. The incomplete resection rate (IRR) was found to be significantly higher in the CSP group compared to the HSP group (risk ratio [RR] 1.57 [1.17-2.11], P = 0.003). Although the CSP group had a higher local recurrence rate than the HSP group, the difference was not statistically significant (RR: 3.98 [0.66-23.84], P = 0.13). The polyp retrieval rates were not significantly different between the two groups (RR: 1.00 [0.99-1], P = 0.22). Perforation was not reported or mentioned in any of the seven studies. The overall immediate bleeding rate was significantly higher in the CSP group than the HSP group (RR: 2.26 [1.63-3.14], P < 0.001), but immediate postpolypectomy bleeding requiring additional intervention was similar between the groups (RR: 1.08 [0.54-2.17], P = 0.82). The delayed bleeding rate (RR: 0.83 [0.45-1.55], P = 0.56) and specific polypectomy time (RR: -0.46 [-1.05-0.12], P = 0.12) were also similar between the groups.

CONCLUSIONS

The meta-analysis shows a significantly higher IRR for CSP compared with HSP when removing small polyps.

Delayed perforation after cold snare polypectomy for small colonic polyps in a patient receiving oral corticosteroids

This case report describes a fatal outcome due to delayed perforation after cold snare polypectomy in a patient with bullous pemphigoid receiving oral corticosteroids. Cold snare polypectomy has become the standard treatment for small colorectal polyps because of the procedure's safety and simplicity. In this case, however, corticosteroid therapy and vasculitis may have caused local necrosis and tearing of the intestinal wall. Corticosteroids are widely used, and perforation after cold snare polypectomy is extremely rare. However, some patients on corticosteroid therapy may have special pathologies, such as in this case, and we advise physicians to use appropriate judgment and extreme caution in determining the indication for endoscopic therapy.

Management of colorectal high-grade dysplasia or cancer resected by cold snare polypectomy: a multicenter exploratory study

BACKGROUND

The clinical course and surveillance strategy for patients who undergo cold snare polypectomy (CSP) for high-grade dysplasia (HGD) or cancer is unclear. We investigated the management of colorectal HGDs and cancers following CSP.

METHODS

This Japanese nationwide multicenter exploratory study was retrospectively conducted on patients who had undergone CSP for colorectal HGDs or cancers and follow-up colonoscopy at least once from 2014 to 2020. We investigated the detection rate of CSP scars, local recurrence rate (LRR), risk factors for local recurrence, and follow-up strategy. This study was registered with the University Hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN000043670).

RESULTS

We included 155 patients with 156 lesions. CSP scars were identified in 22 (31.4%), 41 (54.7%), and 10 (90.9%) patients with curative, borderline, and non-curative resection, respectively. Among them, residual tumors were observed in one (4.5%), six (14.6%), and three (30.0%) cases, respectively. The total LRR was 13.7% (95% confidence interval: 6.8-23.8). R1 resection cases (either horizontal or vertical margins positive for tumors) were associated with local recurrence (p = 0.031). Salvage endoscopic and surgical resections were performed on 21 and 10 patients, respectively. Among them, the proportion of endoscopically suspected residual tumors was significantly higher (p < 0.001) in the residual tumor-positive group (100%) than in the residual tumor-negative group (28.6%).

CONCLUSIONS

LRR after CSP for HGDs or cancers was 13.7% based on scar-identified cases. Salvage endoscopic or surgical resection should be performed according to the curability of the lesion and endoscopic findings during colonoscopic surveillance.

Cold Versus Hot Snare Polypectomy for Small Colorectal Polyps : A Pragmatic Randomized Controlled Trial

BACKGROUND

Although cold snare polypectomy (CSP) is considered effective in reducing delayed postpolypectomy bleeding risk, direct evidence supporting its safety in the general population remains lacking.

OBJECTIVE

To clarify whether CSP would reduce delayed bleeding risk after polypectomy compared with hot snare polypectomy (HSP) in the general population.

DESIGN

Multicenter randomized controlled study. (ClinicalTrials.gov: NCT03373136).

SETTING

6 sites in Taiwan, July 2018 through July 2020.

PARTICIPANTS

Participants aged 40 years or older with polyps of 4 to 10 mm.

INTERVENTION

CSP or HSP to remove polyps of 4 to 10 mm.

MEASUREMENTS

The primary outcome was the delayed bleeding rate within 14 days after polypectomy. Severe bleeding was defined as a decrease in hemoglobin concentration of 20 g/L or more, requiring transfusion or hemostasis. Secondary outcomes included mean polypectomy time, successful tissue retrieval, en bloc resection, complete histologic resection, and emergency service visits.

RESULTS

A total of 4270 participants were randomly assigned (2137 to CSP and 2133 to HSP). Eight patients (0.4%) in the CSP group and 31 (1.5%) in the HSP group had delayed bleeding (risk difference, -1.1% [95% CI, -1.7% to -0.5%]). Severe delayed bleeding was also lower in the CSP group (1 [0.05%] vs. 8 [0.4%] events; risk difference, -0.3% [CI, -0.6% to -0.05%]). Mean polypectomy time (119.0 vs. 162.9 seconds; difference in mean, -44.0 seconds [CI, -53.1 to -34.9 seconds]) was shorter in the CSP group, although successful tissue retrieval, en bloc resection, and complete histologic resection did not differ. The CSP group had fewer emergency service visits than the HSP group (4 [0.2%] vs. 13 [0.6%] visits; risk difference, -0.4% [CI, -0.8% to -0.04%]).

LIMITATION

An open-label, single-blind trial.

CONCLUSION

Compared with HSP, CSP for small colorectal polyps significantly reduces the risk for delayed postpolypectomy bleeding, including severe events.

PRIMARY FUNDING SOURCE

Boston Scientific Corporation.

Cold snare polypectomy versus cold endoscopic mucosal resection for small colorectal polyps: a multicenter randomized controlled trial

BACKGROUND

Cold snare polypectomy (CSP) is recommended for the resection of small colorectal polyps. However, few studies have investigated the efficacy of cold endoscopic mucosal resection (cold EMR) for small polyps. Thus, the aim of this study was to investigate the efficacy and safety of cold EMR compared with CSP for small colorectal polyps.

METHODS

This was a multicenter, randomized trial conducted in three tertiary centers from January 2018 to February 2021. Patients with polyps sized 6-10 mm were randomized to CSP or cold EMR group. After polypectomy, two additional biopsies were performed to assess the completeness of resection. The primary outcome was complete polyp resection rate. Secondary outcomes were total procedure time and rate of adverse events such as immediate bleeding, delayed bleeding, and perforation.

RESULTS

A total of 444 polyps in 327 patients were assessed and randomly assigned to each group. Of those, 425 polyps were finally analyzed based on pathology results. The complete resection rate was not significantly different between cold EMR and CSP groups (91.9% vs 89.8%, p = 0.24). However, the total procedure time was significantly increased in cold EMR (87.6 s vs. 45.8 s, p < 0.001). The rate of polypectomy adverse events was not significantly different between the two groups. No patient had massive bleeding or perforation.

CONCLUSIONS

There was no difference in complete resection rate or adverse events between CSP and cold EMR. However, CSP reduced the total procedure time.

Comparison of complete resection rates in cold snare polypectomy using two different wire diameter snares: A randomized controlled study

BACKGROUND AND AIM

Cold snare polypectomy (CSP) is a standard treatment for small colorectal polyps. This study examined the effect of different snare wire diameters on complete histological resection rate, resection depth, and CSP safety.

METHODS

This randomized controlled trial was conducted at two institutions between June 2019 and March 2021. Eligible colorectal polyps (≤10 mm) were randomly assigned in a 1:1 ratio to receive either CSP with a conventional snare made of normal-diameter wire (0.40 mm) or CSP with a dedicated snare made of thin wire (0.23 mm). The primary endpoint was the complete resection rate determined on histological assessment of the resected specimen.

RESULTS

In total, 254 lesions in 152 patients were included, with 128 and 126 lesions assigned to the normal-diameter wire snare group and the thin-wire snare group, respectively. No significant differences were observed in patient characteristics between the two groups. The histological complete resection rate was significantly higher in the thin-wire snare group than in the normal-diameter wire snare group (70.0% vs 81.0%, P = 0.04). The normal-diameter wire snare group had significantly more cases of unclear horizontal margin evaluation than the thin-wire snare group (28.1% vs 15.9%, P = 0.02). No significant differences were observed between the two groups in the muscularis mucosa and submucosa of the resected specimens or the thickness of the submucosa in the resected specimens.

CONCLUSIONS

CSP with a dedicated thin-wire snare provides more specimens that can be evaluated at the horizontal end and increases the histological complete resection rate.

Underwater versus conventional cold snare polypectomy of colorectal polyps 4-9 mm in diameter: a prospective randomized controlled trial

BACKGROUND AND AIMS

Cold snare polypectomy (CSP) has been reported as safe and effective method for the removal of small colorectal polyps. However, some studies showed low R0 resection rate. Underwater endoscopic mucosal resection is an effective technique to increase the proportions of complete resection. Therefore, the aim was to compare the rate of R0 resection of colorectal polyps 4-9 mm in diameter between conventional CSP (C-CSP) and underwater CSP (U-CSP).

METHODS

This study was a prospective randomized controlled trial. A total of 198 polyps (4-9 mm) in 110 patients were enrolled between December 2019 and June 2020. The polyps were randomized to be treated with either C-CSP (100 polyps) or U-CSP (98 polyps).

RESULTS

The R0 resection rate was significantly higher in U-CSP group than in C-CSP groups (84.7% vs. 59.0%; p < 0.001). The polyp retrieval rate of C-CSP and U-CSP was 94.5% and 100% (p = 0.030). The rate of polyp fragmentation of C-CSP and U-CSP group was 5.3% and 0% (p = 0.027). The resection time and retrieval time were longer in C-CSP than U-CSP (45.0 ± 37.7 s vs. 34.1 ± 21.2 s, p = 0.032 and 51.9 ± 67.7 s vs. 12.7 ± 12.4 s, p < 0.001). No clinically significant bleeding or perforation occurred in either group.

CONCLUSIONS

The results of this study were excellent with U-CSP of 4-9 mm colorectal polyps in terms of R0 resection, polyp retrieval and fragmentation rate, and procedure/retrieval time. Therefore, U-CSP is a safe and effective technique for removing colorectal polyps 4-9 mm in diameter. KCT (0004530).

Effect of cold snare polypectomy for small colorectal polyps

BACKGROUND

Colorectal cancer remains a considerable challenge in healthcare nowadays. Approximately 60%-80% of colorectal cancer is caused by intestinal polyps, and resection of intestinal polyps has been proved to reduce the incidence of colorectal cancer. The vast majority of intestinal polyps can be found during colonoscopy and removed endoscopically. Therefore, more attention has been paid to the development of endoscopic resection of intestinal polyps. In this study, we compared the efficacy and safety of cold snare polypectomy (CSP) and hot snare polypectomy (HSP).

AIM

To investigate the efficacy and safety of CSP and HSP for colorectal polyps.

METHODS

Between January and December 2020, 301 patients with colorectal polyps 4-9 mm in diameter were treated with endoscopic therapy in our hospital, and were divided into the CSP group (n = 154) and HSP group (n = 147). The operating time, incidence of bleeding and perforation, use of titanium clips, and complete resection rate were compared between the two groups.

RESULTS

We included 249 patients (301 polyps). No differences in gender, age, and polyp size, location, shape and type were observed between the CSP and HSP groups, and the resection rates in these two groups were 93.4% and 94.5%, respectively, with no significant difference. The use of titanium clips was 15.6% and 95.9%, the operating time was 3.2 ± 0.5 min and 5.6 ± 0.8 min, the delayed bleeding rate was 0% and 2.0%, and delayed perforation was 0% and 0.7%, in the CSP and HSP groups, respectively.

CONCLUSION

For sessile colorectal polyps < 10 mm, CSP had the same resection rate of impaired tissue integrity as traditional HSP had. The rate of complications was lower in the CSP group. CSP is a safe and effective method for polypectomy.

Endoscopic diagnosis and treatment of early colorectal cancer

Early colorectal cancer refers to cancer in the colorectum that is confined to the mucosa or submucosa and does not invade the muscularis propria, irrespective of lymph node or distant metastasis. As the number of persons undergoing screening colonoscopy increases, the proportion of patients diagnosed with precancerous colorectal lesions and early colorectal cancer also increases. In the last decade, innovative optical technologies for endoscopic diagnosis have been introduced and endoscopic treatment techniques such as endoscopic submucosal dissection have provided major breakthroughs in the management of early colorectal cancer. With these remarkable developments, endoscopic treatment has established itself as an alternative to surgical resection in the treatment of early colorectal cancer. This review will discuss the endoscopic diagnosis and treatment of early colorectal cancer. Furthermore, the unmet needs in this field and the latest research addressing those issues will be summarized.

Endoscopic follow-up of mucosal defect after hot versus cold snare polypectomy in animal model

BACKGROUND AND AIM

Cold snare polypectomy (CSP) has received increasing attention in recent years, but few studies have assessed defect repair after polypectomy. Therefore, we compared the repair of mucosal defect after CSP and hot snare polypectomy (HSP) in a rabbit model.

METHODS

Resection of normal colonic mucosa using both HSP and CSP were performed in 40 male New Zealand white rabbits by an experienced endoscopist. Follow-up colonoscopy was performed after 7 and 15 days by another endoscopist. We assessed mucosal defect repair, status of healing, scar formation, and intraoperative or delayed complications (including perforation and bleeding).

RESULTS

Eight animals died of intraoperative or delayed perforation; follow-up colonoscopy was performed in 32 animals. On follow-up colonoscopy at 7 days after operation, 78.1% cases in the CSP group showed healing of mucosal defect compared with none in the HSP group (P < 0.001); mucosal repair score in the CSP group was significantly higher than HSP group (P < 0.001). On follow-up colonoscopy at 15 days, mucosal defect after CSP had completely healed in all cases (100%) versus 96.9% after HSP (P = 0.313). Among these healed defects, scar formation was observed in 2 of 32 cases in the CSP group compared with 19 of 31 in the HSP group (P < 0.001). Intraoperative perforation rate was significantly higher in the HSP group (15% vs 2.5%; P = 0.048).

CONCLUSIONS

Mucosal defect repair after CSP is quicker compared with HSP and is more likely to result in scarless healing. HSP is more likely to cause perforation in the thin colon walls.

Efficacy of specimen pasting after cold snare polypectomy for pathological evaluation of horizontal margins

Background and study aims  Several studies have reported that pathological horizontal margin evaluation cannot be diagnosed in cold snare polypectomy (CSP) specimens. We conducted a prospective randomized controlled trial to determine the efficacy of pasting CSP specimens on paper for pathological horizontal margins. Patients and methods  This was a single-center, prospective study conducted at Osaka Saiseikai Nakatsu Hospital. In this study, the indications for CSP were adenomas ≤ 10 mm. Colorectal polyps resected by CSP were randomized to the pasting and non-pasting groups after exclusion of fragmented specimens, and the extended CSP specimens pasted on paper were formalin-fixed in the pasting group. The primary endpoint was rate of unclear horizontal margins after CSP. Results  A total of 216 CSP specimens were analyzed. The rate of unclear horizontal margins was significantly lower in the pasting group than in the non-pasting group (15.1 % vs 33.6 %, P  = 0.002). CSP specimen pasting significantly reduced the rate of unclear horizontal margins. On multivariate analysis, non-pasting group (odds ratio [OR], 2.69; 95 % confidence interval [CI], 1.38-5.41; P  = 0.003) and right colon (OR, 1.98; 95 %CI, 1.01-4.01; P  = 0.047) were independent risk factors for unclear horizontal margins in CSP specimens. Conclusions  Pasting the extended specimen is important for accurate pathological examination after CSP.

Resection depth for small colorectal polyps comparing cold snare polypectomy, hot snare polypectomy and underwater endoscopic mucosal resection

Background and study aims  Small colorectal polyps are removed by various methods, including cold snare polypectomy (CSP), hot snare polypectomy (HSP), and underwater endoscopic mucosal resection (UEMR), but the indications for using these methods are unclear. We retrospectively assessed the efficacy of CSP, HSP, and UEMR for small polyps, focusing on the depth of the resected specimens. Patients and methods  Outpatients with non-pedunculated small polyps (endoscopically diagnosed as 6 to 9 mm), resected by two endoscopists between July 2019 and September 2020, were enrolled. We histologically evaluated the specimens resected via CSP, HSP, and UEMR. The main outcome was the containment rate of the muscularis mucosa (MM) and submucosa (SM) tissues. Results  Forty polyps resected via CSP (n = 14), HSP (n = 12), or UEMR (n = 14) were enrolled after excluding 13 polyps with resection depths that were difficult to determine. The rates of specimens containing MM and SM tissue differed significantly (57 % and 29 % for CSP, 92 % and 83 % for HSP, and 100 % and 100 % for UEMR, respectively ( P  = 0.005 for MM and P  < 0.001 for SM tissue). Multiple logistic regression analysis showed UEMR was an independent factor relating to the containment of SM tissue. The thickness of SM tissue by CSP, HSP, and UEMR were 52 μm, 623 μm, and 1119 μm, respectively ( P  < 0.001). The thickness by CSP was significantly less than those by HSP and UEMR ( P  < 0.001, Bonferroni correction). Conclusions  UEMR could be the best method to contain SM tissue without injection. Further studies are needed to evaluate the indication of UEMR for small polyps.

Guidelines for Colorectal Cold Polypectomy (supplement to "Guidelines for Colorectal Endoscopic Submucosal Dissection/Endoscopic Mucosal Resection")

The Japan Gastroenterological Endoscopy Society published the second edition of the "Guidelines for Colorectal Endoscopic Submucosal Dissection/Endoscopic Mucosal Resection" in 2019 to clarify the indications for colorectal endoscopic mucosal resection (EMR) and endoscopic submucosal dissection and to ensure appropriate preoperative diagnoses as well as effective and safe endoscopic treatment in front-line clinical settings. Endoscopic resection with electrocautery, including polypectomy and EMR, is indicated for colorectal polyps. Recently, the number of facilities introducing and implementing cold polypectomy without electrocautery has increased. Herein, we establish supplementary guidelines for cold polypectomy. Considering that the level of evidence for each statement is limited, these supplementary guidelines must be verified in clinical practice.

Depth of the cutting plane with underwater and conventional endoscopic mucosal resection: Post-hoc analysis of a randomized study

BACKGROUND AND AIM

A multicenter randomized controlled trial reported a better R0 resection rate for intermediate-sized (10-20 mm) colorectal polyps with underwater endoscopic mucosal resection (UEMR) than conventional endoscopic mucosal resection (CEMR). To clarify whether UEMR removes enough submucosal tissue in the removal of unpredictable invasive cancers, we investigated the cutting plane depth with UEMR versus CEMR.

METHODS

This was a post-hoc analysis of a randomized controlled trial in which 210 intermediate-sized colorectal polyps were removed in five Japanese hospitals. One pathologist and two gastroenterologists independently reviewed all resected specimens and measured the cutting plane depth. The cutting plane depth was evaluated as (i) maximum depth of submucosal layer and (ii) mean depth of submucosal layer, calculated using a virtual pathology system.

RESULTS

We identified 168 appropriate specimens for the evaluation of the cutting plane depth, resected by UEMR (n = 88) and CEMR (n = 80). The median resection depth was not significantly different between UEMR and CEMR specimens, regardless of the measurement method ([i] 1317 vs 1290 μm, P = 0.52; [ii] 619 vs 545 μm, P = 0.32). All specimens in the UEMR and CEMR groups contained substantial submucosa and no muscularis propria.

CONCLUSIONS

The cutting plane depth with UEMR was comparable with that with CEMR. UEMR can be a viable alternative method that adequately resects the submucosal layer for the histopathological assessment of unpredictable submucosal invasive cancers.

Safety and Efficacy of Cold Snare Polypectomy Without Submucosal Injection for Large Sessile Serrated Lesions: A Prospective Study

BACKGROUND & AIMS

Cold snare polypectomy (CSP) has become the standard resection method for small colorectal polyps (<10 mm). Sessile serrated lesions (SSL) have low prevalence of advanced histology irrespective of size, and thus could be amenable to CSP. In this study, we evaluated the safety and efficacy of CSP for SSLs ≥10 mm.

METHODS

Between November 2018 and January 2020, we prospectively enrolled 300 consecutive patients who underwent CSP for 474 SSLs ≥10 mm. To delineate SSL borders, indigo carmine chromoendoscopy and/or image-enhanced endoscopy was conducted. Piecemeal CSP (pCSP) was performed in cases where en-bloc resection was difficult. Biopsy specimens were obtained from the margins of the post-polypectomy defect to confirm complete resection. Surveillance colonoscopy was performed to screen for local recurrence.

RESULTS

All lesions were successfully resected using CSP without submucosal injection. The median diameter of the resected lesions was 14 mm, and pCSP was used to resect 106 (22%) lesions. Post-polypectomy biopsies revealed residual serrated tissue in only one case (0.2%). Adverse events included immediate bleeding in 8 (3%) patients; no delayed bleeding events occurred, irrespective of the use of antithrombotic drugs. During a 7-month median follow-up period, surveillance colonoscopies were performed for 384 lesions (81%), and no local recurrences were detected.

CONCLUSIONS

CSP without submucosal injection is a safe and effective treatment for SSLs ≥10 mm. UMIN Clinical Trials, Number: UMIN000034763.

Influence of early colorectal cancer component on the positive margins after endoscopic resection: a retrospective study

Background

Endoscopic treatment methods for early colorectal cancer (ECRC) mainly depend on the size and morphology. It is unclear whether different endoscopic resection methods could achieve curative resection for ECRC confined in the mucosa. The study was designed to compare the rate of positive vertical margin (VM) of ECRC with advanced adenomas (AAs) including adenoma > 1 cm, villous adenoma, high-grade intraepithelial neoplasia/dysplasia stratified by different endoscopic resection methods.

Methods

Rate of positive VM for 489 ECRCs including Intramucosal (pTis) and superficial submucosal invasion (pT1) carcinomas were compared with those of 753 AAs stratified by different endoscopic resection methods using Chi-squared test. Multivariate logistic model was performed to investigate the risk factors of positive VM for different endoscopic resection methods.

Results

The pTis ECRC exhibited a similar rate of positive VM as that of AAs for en bloc hot snare polypectomy (HSP, 0% Vs. 0.85%, P = 0.617), endoscopic mucosal resection (EMR, 0.81% vs. 0.25%, P = 0.375) and endoscopic submucosal dissection (ESD, 1.82% Vs. 1.02%, P = 0.659). The pTis carcinoma was not found to be a risk factor for positive VM by en bloc EMR (P = 0.349) or ESD (P = 0.368). The en bloc resection achieved for pT1a carcinomas exhibited similar to positive VM achieved through ESD (2.06% Vs. 1.02%, P = 1.000) for AAs. Nonetheless, EMR resulted in higher risk of positive VM (5.41% Vs. 0.25%, P < 0.001) for pT1a carcinomas as compared to AAs. The pT1a invasion was identified as a risk factor for positive VM in polyps with en bloc EMR (odds ratio = 23.90, P = 0.005) but not ESD (OR = 2.96, P = 0.396).

Conclusion

Collectively, the pTis carcinoma was not found to be a risk factor for positive VM resected by en bloc HSP, EMR or ESD. Additionally, ESD may be preferred over EMR for pT1a carcinomas with lower rate of positive VM.

Real-world local recurrence rate after cold polypectomy in colorectal polyps less than 10 mm using propensity score matching

BACKGROUND

Cold polypectomy (CP) is a simple and safe procedure for polyps less than 10 mm in size; however, there is concern about local recurrence following CP because of unidentified margins of excised specimens and the lack of tumor suppression effect by coagulation. Some clinical trials have evaluated local persistent recurrence; their results suggest that a higher rate of local recurrence has not been documented so far. There were few reports that observed the course over long periods of time after CP in clinical practice.

AIM

To evaluate the presence of local recurrence following CP and hot polypectomy (HP) using propensity score matching.

METHODS

We analyzed 275 patients who underwent polypectomy for non-pedunculated colorectal polyps less than 10 mm (959 Lesions) between October 2016 and 2017 and underwent follow-up endoscopy subsequently. We divided them into the CP group (706 Lesions), wherein CP was performed, and the HP group (253 Lesions), wherein HP was performed. Using propensity score matching, we extracted 215 Lesions in each group and evaluated the local recurrence and content of CP in the real clinic and adverse events using medical records.

RESULTS

After propensity score matching, there were no significant differences in the patients’ and their endoscopic background (age, use of antithrombotics, indications, size, morphology, location of polyps, and polypectomy device) between the groups. The mean duration between colorectal polypectomy and the next follow-up colonoscopy was 17.5 ± 7.1 (range, 6-39) mo in the CP group and 15.7 ± 6.0 (range, 6-35) mo in the HP group, which was significantly longer in the CP group (P = 0.005). The local recurrence rate was 0.93% in the CP group and 0.93% in the HP group, without a significant difference (P = 0.688). Additionally, no differences were observed in the macroscopic en bloc resection rate, histopathological complete resection rate, and pathological results between the groups. Adverse events did not occur in either group.

CONCLUSION

Local recurrence after CP was equivalent to that following HP in clinical practice. CP is useful and safe in the treatment of non-pedunculated polyps of less than 10 mm.

Current Endoscopic Resection Techniques for Gastrointestinal Lesions: Endoscopic Mucosal Resection, Submucosal Dissection, and Full-Thickness Resection

Background

Endoscopic resection of dysplastic lesions in early stages of cancer reduces mortality rates and is recommended by many national guidelines throughout the world. Snare polypectomy and endoscopic mucosal resection (EMR) are established techniques of polyp removal. The advantages of these methods are their relatively short procedure times and acceptable complication rates. The latter include delayed bleeding in 0.9% and a perforation risk of 0.4-1.3%, depending on the size and location of the resected lesion. EMR is a recent modification of endoscopic resection. A limited number of studies suggest that larger lesions can be removed en bloc with low complication rates and short procedure times. Novel techniques such as endoscopic submucosal dissection (ESD) are used to enhance en bloc resection rates for larger, flat, or sessile lesions. Endoscopic full-thickness resection (EFTR) is employed for non-lifting lesions or those not easily amenable to resection. Procedures such as ESD or EFTR are emerging standards for lesions inaccessible to EMR techniques.

Summary

Endoscopic treatment is now regarded as first-line therapy for benign lesions.

Key Message

Endoscopic resection of dysplastic lesions or early stages of cancer is recommended. A plethora of different techniques can be used dependent on the lesions.

Cold versus hot polypectomy/endoscopic mucosal resection-A review of current evidence

Background

Colonoscopy with polypectomy substantially reduces the risk of colorectal cancer (CRC) but interval cancers still account for 9% of all CRCs, some of which are due to incomplete resection.

Aim

The aim of this review is to compare the outcomes of cold and hot endoscopic resection and provide technical tips and tricks for optimizing cold snare polypectomy.

Results

Cold snare polypectomy (CSP) is the standard technique for small (≤10 mm) colorectal polyps. For large colonic polyps (>10 mm), hot resection techniques with use of electrocautery (polypectomy or endoscopic mucosal resection) were recommended until recently. However, the use of electrocoagulation brings serious adverse effects in up to 9% of the patients, such as delayed bleeding, post‐polypectomy syndrome and perforation. In recent years, efforts have been made to improve the polypectomy with cold snare in order to avoid these adverse effects of electrocoagulation without compromising the efficacy of the resection. Several authors have recently shown that the complication rates of CSP of polyps >10 mm is close to zero and recurrence rates varies between 5‐18%. Lower recurrence rates are found in serrated lesions (<8%).

Colonoscopy screening and surveillance guidelines

The Colonoscopy Screening and Surveillance Guidelines were developed by the Japan Gastroenterological Endoscopy Society as basic guidelines based on the scientific methods. The importance of endoscopic screening and surveillance for both detection and post-treatment follow-up of colorectal cancer has been recognized as essential to reduce disease mortality. There is limited high-level evidence in this field; therefore, we had to focus on the consensus of experts. These clinical practice guidelines consist of 20 clinical questions and eight background knowledge topics that have been determined as the current guiding principles.

Endoscopic polypectomy devices

Video 1Use of submucosal injection prior to en-bloc endoscopic mucosal resection.Video 2Use of a detachable loop ligating device prior to hot snare resection of a pedunculated polyp.

Evidence-based clinical practice guidelines for management of colorectal polyps

BACKGROUND

The Japanese Society of Gastroenterology (JSGE) published ''Daicho Polyp Shinryo Guideline 2014'' in Japanese and a part of this guideline was published in English as "Evidence-based clinical practice guidelines for management of colorectal polyps" in the Journal of Gastroenterology in 2015. A revised version of the Japanese-language guideline was published in 2020, and here we introduce a part of the contents of revised version.

METHODS

The guideline committee discussed and drew up a series of clinical questions (CQs). Recommendation statements for the CQs were limited to items with multiple therapeutic options. Items with established conclusions that had 100% agreement with previous guidelines (background questions) and items with no (or old) evidence that are topics for future research (future research questions: FRQs) were given descriptions only. To address the CQs and FRQs, PubMed, ICHUSHI, and other sources were searched for relevant articles published in English from 1983 to October 2018 and articles published in Japanese from 1983 to November 2018. The Japan Medical Library Association was also commissioned to search for relevant materials. Manual searches were performed for questions with insufficient online references.

RESULTS

The professional committee created 18 CQs and statements concerning the current concept and diagnosis/treatment of various colorectal polyps, including their epidemiology, screening, pathophysiology, definition and classification, diagnosis, management, practical treatment, complications, and surveillance after treatment, and other colorectal lesions (submucosal tumors, nonneoplastic polyps, polyposis, hereditary tumors, ulcerative colitis-associated tumors/carcinomas).

CONCLUSIONS

After evaluation by the moderators, evidence-based clinical practice guidelines for management of colorectal polyps were proposed for 2020. This report addresses the therapeutic related CQs introduced when formulating these guidelines.

Histopathologic features and fragmentation of polyps with cold snare defect protrusions

BACKGROUND AND AIMS

Cold snare defect protrusions (CSDPs) include muscularis mucosa (MM) and submucosa tissue. CSDPs are thought to result from fragmentation of the specimen during shallow excision. Our aim in this study was to clarify whether CSDPs are associated with polyp fragmentation.

METHODS

We retrospectively analyzed 1026 neoplastic colorectal polyps resected by cold snare polypectomy for which the presence or absence of CSDPs was assessed from the endoscopic image. All prepared specimens were reviewed and assessed for the presence or absence of polyp fragmentation, and the proportion of MM on the stump was measured. In addition, the risk factors for CSDP occurrence were evaluated.

RESULTS

CSDPs occurred in 116 of the 1026 polyps (11.3%). Polyp fragmentation was significantly associated with the occurrence of CSDP on univariate analysis (odds ratio [OR], 3.74; P < .001) and multivariate analysis (OR, 3.13; P < .001). The proportion of MM >50% was significantly lower in the CSDP group than in the non-CSDP group (51.5% vs 70.9%, P < .001). CSDPs were significantly associated with a large polyp size (OR, 1.32; P = .007) and a large specimen size (OR, 1.24; P < .001) on multivariate analysis.

CONCLUSIONS

The occurrence of CSDP was associated with less MM on the stump and fragmentation of the specimen. Clinically, the presence of CSDP is a good indicator of polyp fragmentation.

Efficacy and safety of cold-snare endoscopic mucosal resection for colorectal adenomas 10 to 14 mm in size: a prospective observational study

BACKGROUND AND AIMS

Cold-snare endoscopic mucosal resection (CS-EMR) has been adapted in a piecemeal fashion as a safe and effective procedure for resection of colorectal polyps ≥10 mm. However, few data are available on en bloc CS-EMR for adenomas of 10 to 14 mm. Thus, this study evaluated the efficacy and safety of CS-EMR for these colorectal adenomas.

METHODS

In this single-arm, prospective, observational study, patients with at least 1 slightly elevated and sessile colorectal adenoma measuring 10 to 14 mm were recruited to undergo CS-EMR. The primary outcome was histological complete resection rate by CS-EMR, which was defined as en bloc resection, with a pathologically negative vertical margin and no neoplastic tissue obtained from 4 quadrants of the mucosal defect margin. Secondary outcomes were en bloc resection rate by CS-EMR, failure rate of CS-EMR, and the incidence of adverse events.

RESULTS

A total of 80 polyps from 72 patients were included. CS-EMR failed in 11 lesions (13.7%), all of which were resected using a high-frequency electric current. The rates of en bloc resection and histologic complete resection by CS-EMR were 82.5% (66 of 80) and 63.8% (51 of 80), respectively. No bleeding occurred during the CS-EMR procedure, and there was no delayed bleeding or perforation at the site where CS-EMR was performed.

CONCLUSIONS

CS-EMR can be safely performed in an en bloc fashion for some colorectal adenomas measuring 10 to 14 mm. However, there is room for improvement regarding the resectability and evaluation of the vertical margin after CS-EMR. (Clinical trial registration number: UMIN000031248.).

Impact of submucosal saline solution injection for cold snare polypectomy of small colorectal polyps: a randomized controlled study

BACKGROUND AND AIMS

Cold snare polypectomy (CSP) of small colorectal polyps is widely used. However, the technique is still troubled by insufficient resection depth, which may prevent precise pathologic evaluation. In this study, we investigated whether submucosal injection of saline solution helps to achieve deeper resection in CSP.

METHODS

The study was a single-center, prospective, randomized trial. Patients with small (3- to 10-mm diameter) nonpedunculated adenomatous or sessile serrated colorectal polyps were randomly allocated to either conventional CSP (C-CSP) or CSP with submucosal injection (CSP-SI). Primary outcome was the rate of complete muscularis mucosae (MM) resection, defined by the proportion of MM under the tumor more than 80% of the tumor's horizontal dimension. Secondary outcomes were the rates of negative lateral and vertical margins, fragmentation of resected specimens, conversion to hot snare mucosal resection, intraprocedural bleeding, delayed bleeding, and perforation.

RESULTS

Two hundred fourteen patients were randomly assigned to the CSP-SI (n = 107) or C-CSP (n = 107) group. The rate of complete MM resection was 43.9% in the CSP-SI group and 53.3% in the C-CSP group, a statistically insignificant difference. The rates of negative lateral margin and vertical margin (42.3% and 56.7%, respectively) in the CSP-SI group were significantly lower than those (58% and 76%) in the C-CSP group (P = .03 and P = .006, respectively). There was no polypectomy-related major bleeding or perforation.

CONCLUSIONS

Saline solution injection into the submucosa did not improve the resection depth of CSP of small colorectal polyps, and the method resulted in lower rates of negative lateral and vertical margins of resected lesions. (Clinical trial registration number: UMIN000037980.).

Endoscopic prediction of advanced histology in colorectal lesions sized <10 mm using the Japan Narrow-band imaging Expert Team classification

BACKGROUND AND AIM

Endoscopic diagnosis of advanced histology in colorectal lesions sized <10 mm is essential for appropriate selection of resection methods. The Japan Narrow-band imaging Expert Team (JNET) classification has been recently validated for the evaluation of colorectal lesions. Our objective was to investigate the diagnostic value of the JNET classification for advanced histology in colorectal lesions sized <10 mm.

METHODS

We enrolled 680 patients with 1472 colorectal lesions sized <10 mm diagnosed according to the JNET classification and who subsequently underwent endoscopic or surgical resection between January and December 2017. We retrospectively examined the relationship between the JNET findings and pathological histology. Multivariate analysis was carried out to assess the predictive power of the JNET findings and clinical characteristics of lesions.

RESULTS

Advanced histology was present in 29 (2.0%) lesions. Advanced histology was absent in 68 lesions diagnosed as JNET type 1, whereas 1389 lesions diagnosed as JNET type 2A included 19 lesions of advanced histology (1.4%) with high-grade dysplasia alone. Eleven lesions diagnosed as JNET type 2B comprised eight lesions of advanced histology (72.7%) with four high-grade dysplasia and four submucosal invasive cancer, and two lesions diagnosed as JNET type 3 were submucosal invasive cancer. Multivariate analysis showed that JNET type 2B + 3 was a stronger predictive factor for advanced histology than other clinical risk factors.

CONCLUSION

Narrow-band imaging with magnification according to the JNET classification may be a useful modality for identification of advanced histology in colorectal lesions sized <10 mm.

Efficacy and safety of three different endoscopic methods in treatment of 6-20 mm colorectal polyps

Objective: Endoscopic resection of colorectal polyps is widely established as the optimal method to manage precancerous lesions. But the optimal technique for removal of the polyps is uncertain. The aim of this study was to compare the efficacy and safety of three methods for the management of 6-20mm colorectal polyps.Methods: A prospective, randomised controlled trial was conducted at the 900TH Hospital of Joint Logistics Support Force in Fujian, China. Endoscopically diagnosed colorectal polyps, 6-20 mm in size, were randomly assigned to the cold snare polypectomy (CSP), cold snare endoscopic mucosal resection (CS-EMR) or endoscopic mucosal resection (EMR) group. After polypectomy, additional 3-5 forceps biopsies by leading narrow-band imaging (NBI) were performed at the base and margins of polypectomy sites to assess the presence of residual polyp tissue and all samples were sent for histopathological analysis to assess completeness of resection. Polypectomy timing, tissue retrieval and complications were recorded at the time of the procedure.Results: A total of 781 polyps in 404 patients were assessed and randomly assigned to each group. Of these, 763 polyps were finally analyzed based on the pathology results. The complete resection rates with CSP, CS-EMR and EMR were 81.6%, 94.1% and 95.5%, respectively (p < .001). The intraprocedural bleeding rate, immediately after polypectomy, was significantly higher in the CSP group than in the CS-EMR and EMR group (9.4% vs. 4.4% vs. 1.9%; p < .001). However,delayed bleeding was higher in the EMR group than in the CSP and CS-EMR group (2.6% vs. 1.2% vs. 0.8%, respectively; p = .215). In the multivariate analysis showed that the operation method, lesion size, morphology and the number of resection were independent risk factors for complete resection rate (CRR) (p < .05), but the location and pathological classification of polyps had no significant influence on CRR.Conclusions: CS-EMR is safe and effective in the treatment of 6-20 mm colorectal polyps. Especially for 6-15 mm non-pedunculated polyps, CS-EMR has a high histological complete resection rate comparable to EMR, and retains the low risk of delayed complications after polypectomy with cold snare. CS-EMR is expected to become a more valuable new cold-cutting technique after cold snare polypectomy.

Underwater cold snare polypectomy for colorectal adenomas

BACKGROUND AND AIM

Cold snare polypectomy (CSP) is a safe treatment for colorectal adenomas. However, the R0 resection rate is not sufficiently high because of inadequate resection of muscularis mucosa. We hypothesized that CSP in an underwater environment could improve this procedure by helping to safely achieve resection containing the muscularis mucosa. We have named this procedure underwater cold snare polypectomy (UCSP). We aimed to investigate the efficacy and safety of UCSP for colorectal adenomas.

METHODS

Between May 2017 and April 2018, patients diagnosed with colorectal adenomas <9 mm underwent UCSP. After follow-up colonoscopy 3 weeks later, the patients post-UCSP scars were biopsied. Outcomes were compared with those of a historical control group who underwent conventional CSP in our previous study using propensity score-matching methods.

RESULTS

Overall, 224 lesions in 65 patients were prospectively resected by UCSP. Pathologically, 209 lesions were adenomas (4.5 ± 1.5 mm) including one intramucosal carcinoma. Only one pathological residual adenoma was identified, but there was no significant difference in the residual rate between the UCSP and CSP groups (both 1.0%). No complications were observed. R0 resection rate and rate of area containing the muscularis mucosa in the UCSP group were significantly higher than those in the CSP group (80.2% vs 32.7%, P < 0.001; 50.0% vs 35.3%, P = 0.015).

CONCLUSION

Underwater cold snare polypectomy for diminutive and small colorectal adenomas was safe and effective from the perspective of pathological complete resection, which is likely facilitated by achieving an adequate depth of resection.

Cold snare polypectomy: Indications, devices, techniques, outcomes and future

Colonoscopy has been shown to reduce the risk of colon cancer by enabling the removal of precancerous lesions. Although cold snare and hot snare polypectomy have similar retrieval rates and complete resection rates, rates of delayed bleeding tend to be lower with cold snare polypectomy than with hot snare polypectomy, especially for patients taking antithrombotic agents. However, among cold snares there may be differences in terms of the completeness of polyp excision, as complete removal appears more likely with thin-wire dedicated cold snares compared to the traditional, thick-wire cold snares. Cold snare polypectomy may be especially well suited for use in patients taking antithrombotic agents, due to its minimal risk of delayed bleeding. Histological analyses suggest that cold snare polypectomy causes less damage to blood vessels in the submucosal layers, which results in a reduced incidence of hemorrhage compared to hot snare polypectomy. However, cold snare removal of small polyps may result in fragmentation of small specimens during collection and concerns as to whether the resection is complete. An endoscopy biomarker of effective cold snare polypectomy technique is needed to ensure complete removal of non-pedunculated colorectal polyps ≤10 mm. Future uses of cold snare polypectomy may include piecemeal removal of sessile serrated adenoma/polyp lesions >10 mm. Currently, cold snare polypectomy should be considered a primary method for colorectal polyps of less than 10 mm, especially those in the 4- to 10-mm range.

Endoscopic prediction of advanced histology in diminutive and small colorectal polyps

BACKGROUND AND AIM

Most polyps detected during colonoscopies are diminutive or small, and they rarely have advanced histology. Real-time prediction of advanced histology would help clinicians to assess the need for pathological evaluation. Here, we investigated endoscopic predictors of advanced histology in diminutive and small polyps.

METHODS

Consecutive patients with adenomatous polyps (<10 mm) removed endoscopically from January 2013 to December 2014 at a single tertiary cancer center were eligible for inclusion. Two endoscopists reviewed all endoscopic images to identify significant findings associated with advanced histology using multivariate models. The sensitivity, specificity, and negative predictive value of the identified endoscopic predictors for advanced histology were calculated.

RESULTS

Of 6170 polyps (4746 diminutive) removed from 2611 patients, 320 (5.2%) showed advanced histology, including five submucosal invasive cancers. In multivariate analysis, advanced histology was significantly associated with the following: loss of lobulation (odds ratio [OR] 61.7; 95% confidence interval [95% CI]: 19.1-199.0); heterogeneity in mucosal patterns (OR 29.0; 95% CI: 14.6-57.3); non-polypoid growth (OR 15.7; 95% CI: 4.4-55.5); white spots (OR 13.5; 95% CI: 7.8-23.5); and surface redness (OR 6.6; 95% CI: 3.0-14.5); and irregular capillary pattern (OR 4.8; 95% CI: 2.5-9.1). These significant predictors successfully predicted all submucosal invasive cancers as advanced histology. The sensitivity, specificity, and negative predictive values were 37.2%, 97.8%, and 96.6%.

CONCLUSIONS

We identified six endoscopic predictors for advanced histology in diminutive or small colon polyps. Diminutive and small polyps lacking these predictors would not be considered to have advanced histology.