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

Mechanisms of cutting soft tissues using snare-type tools

Cold snare polypectomy (CSP) is the predominant method for removing colonic polyps under 6 mm, utilizing snare-type tools as cutting tools. However, complete resection rates often decrease due to occasional cutting failure. Understanding the cutting mechanisms of snare-type tools is thus crucial for optimizing both the tool and procedure. Research on CSP has primarily focused on surgical case studies, with limited focus on the snare tools. This study investigates the cutting mechanisms of snare-type tools, examining the effects of cutting speed and snare properties on cutting force. The results show that the internal tissue fractures first during CSP, followed by the external tissue. High cutting speeds and thin wire ropes reduce the cutting force required and produce flatter cut cross-sections. Cold snare defect protrusions are primarily due to the high toughness and strength of the submucosa layer tissue, which impedes internal tissue fracture. These findings enhance the understanding of the internal fracture mechanism of soft tissue and provide valuable insights for optimizing snare-type tools, potentially improving the efficacy and safety of polyp resection procedures.

A comprehensive meta-analysis comparing the effectiveness and safety of cold snare polypectomy and hot snare polypectomy in removing colorectal polyps ≤ 10 mm

OBJECTIVE

The optimal methods for removing polyps remain controversial, especially for polyps ≤ 10 mm. We aim to combine the latest evidence to evaluate and compare the effectiveness and safety of cold snare polypectomy (CSP) and hot snare polypectomy (HSP) in the removal of colorectal polyps ≤ 10 mm in size.

METHODS

We performed an extensive search across multiple databases, including PubMed, Embase, Cochrane, and Web of Science, with the search period ending in April 2023, for randomized, controlled trials comparing the effectiveness and/or safety of CSP and HSP for the removal of ≤ 10 mm colorectal polyps. The final outcomes included complete resection rate, operation time, and postoperative adverse event (including immediate bleeding, delayed bleeding, and perforation) rates.

RESULTS

A total of 14 eligible randomized, controlled trials were included involving 7,460 patients and 15,829 polyps. The incidence of immediate bleeding was observed to be more prevalent in CSP in contrast to HSP, and the disparity was statistically notable (OR = 2.18, 95 % CI: 1.43-3.30, I2 = 36 %, p = 0.0003). The incidence of delayed bleeding was observed to be lower in CSP in contrast to HSP, and this difference was statistically significant (OR = 0.30, 95 % CI: 0.15-0.58, I2 = 0 %, p = 0.0003). Procedure time: both total colonoscopy time and specific polypectomy time were shorter in CSP versus HSP (MD = -5.92, 95 % CI: -9.70 to -2.14, I2 = 96 %, p = 0.002; MD = -0.56, 95 % CI: -0.91 to -0.20, I2 = 77 %, p = 0.002). There were no statistically significant differences in complete resection and polyp retrieval rate between CSP and HSP.

CONCLUSION

CSP is as effective and safe as HSP for ≤ 10 mm colorectal polyps, while effectively reducing the risk of delayed bleeding and shortening procedure time.

Mechanism behind reduced resection ability of bent snares during cold snare polypectomy

Accidental bending of the snare sheath occasionally occurs during cold snare polypectomy (CSP). We aimed to demonstrate whether snare bending reduces resection ability and, if it does, what causes this reduction. Using currently available CSP snares and prototype snares, we investigated changes in the resection ability of bent snares as well as the stiffness of their sheaths and wire spindles. Furthermore, to evaluate the performance of the bent snares, we measured the completion rate of CSP for 5-mm-diameter pseudo-lesions on the porcine rectal mucosa. Snare bending significantly decreased resection ability and wire spindle stiffness. Compared with bending the snares once, bending the snares five times further decreased the resection ability and wire spindle stiffness. A strong correlation was observed between wire spindle stiffness and resection ability after snare bending (correlation coefficient = 0.82; P < 0.001). Additionally, snare bending reduced the completion rate of CSP. Bending a CSP snare causes decreased wire spindle stiffness, thereby reducing its resection ability and potentially lowering the resection completion rate. The resection ability cannot be restored; therefore, snare replacement is recommended.

Cold snare endoscopic resection for subepithelial tumors of the upper third of the esophagus

Although most esophagus subepithelial tumors are benign, the possibility of malignancy cannot be completely ruled out and it can gradually increase, leading to symptoms such as dysphagia, so removal is still recommended. The narrow cavity and thin walls of the upper esophagus, as well as movement caused by breathing and heartbeat, makes it difficult to perform operation by endoscopy or surgery. Cold snare pulpectomy may been used to remove subepithelial tumors of the upper third of the esophagus due to a low risk of adverse events and short procedure time.

High‐Performance Dedicated Snares with Tip Attachments can Overcome Current Disadvantages in Cold Snare Polypectomy

Cold snare polypectomy (CSP) has the disadvantage of a lower histopathological complete resection rate (HCRR) because blunt resection using CSP‐dedicated snares (DSs) causes mucosal retraction into the sheath during capture/resection. In this study, attachments are designed to narrow the sheath tip's inner diameter from 1.8 to 1.3‒1.1 mm to prevent mucosal retraction. Eight prototype snares with different component characteristics are combined with these attachments. Additionally, product version DS with attachment (Smart Snare Cold) and existing DSs, such as Exacto Cold Snare, are prepared. For snare performance evaluation, the force required to resect (FRR) human colonic mucosa, mucosal retraction amount (MRA), and clinical data are obtained. The attachments that narrowed the inner diameter to 1.3 or 1.1 mm reduce the FRR to 74.9%−93.8% and 68.0%−84.9%, respectively, and reduce the MRA to 21.0%−35.3% and 15.1%−26.8%, respectively. Thus, the reduced inner diameter improves resection ability and prevents mucosal retraction. The clinical findings show that Smart Snare Cold has significantly higher muscularis mucosa resection rates and HCRRs than Exacto Cold Snare (P < 0.001 and P = 0.003, respectively). Thus, the novel DS with tip attachment improves the HCRR and overcomes the current CSP disadvantage by simultaneously improving resection ability and preventing mucosal retraction.

Risk factors and prediction model for delayed bleeding after cold snare polypectomy: a retrospective study

BACKGROUND

Delayed bleeding (DB) is a serious complication after cold snare polypectomy (CSP) for polyps in the colon. The present study aimed to investigate the incidence and risk factors of DB after CSP and to develop a risk-scoring model for predicting DB.

METHODS

A retrospective study was conducted in four Chinese medical institutions. 10650 patients underwent CSP from June 2019 to May 2023. The study analyzed the rate of DB and extracted the general clinical information and polyp-related information of patients with postoperative DB. As a control, non-DB patients who received CSP at the same 4 hospitals were analyzed. A multivariate Cox regression analysis was performed to develop the prediction model. The model was further validated using a Kaplan-Meier log-rank analysis, receiver operating characteristic curve (ROC) plot and risk plot.

RESULTS

In our study, we found a 0.24% rate of DB and the risk factors were history of hypertension, hyperlipidemia, antithrombotics use, antiplatelet use, anticoagulant use, abdominal operation, sigmoid colon lesion, hematoma, cold snare defect protrusion, polyp size, wound size, the grade of wound bleeding, and morphology of Ip. These factors were incorporated into the prediction model for DB after CSP. For 1, 3, and 5 days of bleeding, the AUC of the ROC curve was 0.912, 0.939, and 0.923, respectively. The Kaplan-Meier analysis indicated that the high-risk group had a significantly higher risk of DB than the low-risk group.

CONCLUSIONS

This study screened the risk factors and established a prediction model of DB after CSP. The results may help preventing and reducing the DB rate after CSP of colorectal polyps.

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.

Bleeding After Endoscopic Resection of Colonic Adenomatous Polyps Sized 4-10 mm

Introduction: Colonoscopy with polypectomy is an efficacious procedure in reducing the risk of colorectal cancer development, the precursor are adenomatous polyps. The most common method for resection of polyps measuring 4-10 mm are cold (CSP) and hot snare polypectomy (HSP). CSP has a lower incidence of adverse events, especially delayed post-polypectomy bleeding. Aim: To evaluate the presence of immediate and delayed bleeding in the cold snare polypectomy of sub-centimeter polyps of the colon compared with hot snare polypectomy. Materials and Methods: This prospective clinical study is comprised all patients who were incidentally detected to have adenomatous colonic polyps measuring 4-10 mm during a colonoscopy screening. Polypectomy was done with (hot snare) or without electrocautery (cold snare). After removal of polyps, immediate bleeding, delayed bleeding, and methods for were analyzed. Results: The CSP and HSP groups included 116 patients, 113 (54.4%) polyps in 61 (52.6%) patients with CSP while 95 (45.6%) polyps in 55 (47.4%) patients with HSP. 25 (22.1%) polyps after CSP had immediate bleeding. In 5 patients (20.0%), five hemostatic clips were inserted after CSP for bleeding longer than 150 sek. The average percentage difference between immediate bleeding versus total number of resected polyps using the cold snare method is not statistically significant (p<0.05) (Difference test, p=0.0000). Delayed bleeding was not registered using this method. In the second investigated group (HSP), one patient had delayed bleeding. This was stopped with 2 clips. Immediate bleeding was not registered. Conclusion: CSP is safer than HSP in resecting colon polyps sized 4-10 mm, without risk of delayed bleeding.

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.

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.

Endoscopic techniques for gastric neuroendocrine tumors: An update

Gastric neuroendocrine neoplasms (gNENs) are a rare type of gastric neoplasm, even if their frequency is increasing according to the latest epidemiologic revisions of the main registries worldwide. They are divided into three main subtypes, with different pathogeneses, biological behaviors, and clinical characteristics. GNEN heterogeneity poses challenges, therefore these neoplasms require different management strategies. Update the knowledge on the endoscopic treatment options to manage g-NENs. This manuscript is a narrative review of the literature. In recent years, many advances have been made not only in the knowledge of both the pathogenesis and the molecular profiling of gNENs but also in the endoscopic expertise towards innovative treatment options, which proved to be less aggressive without losing the capability of being radical. The endoscopic approach is increasingly applied in the field of gastrointestinal (GI) luminal neoplasms, and this is true not only for adenocarcinomas but also for gNENs. In particular, different techniques have been described for the endoscopic removal of suspected lesions, ranging from classical polypectomy (cold or hot snare) to endoscopic mucosal resection (both with “en bloc” or piecemeal technique), endoscopic submucosal dissection, and endoscopic full-thickness resection. GNENs comprise different subtypes of neoplasms with distinct management and prognosis. New endoscopic techniques offer a wide variety of approaches for GI localized neoplasms, which demonstrated to be appropriate and effective also in the case of gNENs. Correct evaluation of size, site, morphology, and clinical context allows the choice of tailored therapy in order to guarantee a definitive treatment.

Colorectal cold snare polypectomy: Current standard technique and future perspectives

It has been shown that resection of adenomatous colorectal polyps can reduce mortality due to colorectal cancer. In daily clinical practice, simpler and safer methods of colorectal polypectomy have been sought to enable endoscopists to resect all detected lesions. Among these, cold snare polypectomy (CSP) is widely used in clinical practice because of its advantages in shortening procedure time, reducing delayed bleeding risk, and lowering treatment costs, while maintaining a similar complete resection rate for lesions smaller than 10 mm when compared to conventional hot snare polypectomy. This review introduces the findings of previous studies that investigated the efficacy and safety of the CSP procedure for nonpedunculated polyps smaller than 10 mm, and describes technical points to remember when practicing CSP based on the latest evidence, including using a thin wire snare specifically designed for CSP, and observing the surrounding mucosa of the resection site with chromoendoscopy or image-enhanced endoscopy to ensure that there is no residual lesion. This review also describes the potential of expanding the indication of CSP as a treatment for lesions larger than 10 mm, those with pedunculated morphology, those located near the appendiceal orifice, and for patients under continuous antithrombotic agent therapy. Finally, the perspective on optimal treatments for recurrent lesions after CSP is also discussed, despite the limited related evidence and data.

Bleeding Risk With Cold Snare Polypectomy of ≤10 mm Pedunculated Colon Polyps

OBJECTIVES

Pedunculated polyps (PPs) in the colon are usually resected with hot snare polypectomy to prevent immediate postpolypectomy bleeding (IPPB). This study aimed to evaluate the safety of CSP of <10 mm PPs.

MATERIALS AND METHODS

Patients undergoing colonoscopy from February 18, 2019, to April 24, 2020, and were found to have at least 1 ≤10 mm PP resected with CSP were included prospectively in a continuous quality improvement project to assess the risk of IPPB and delayed postpolypectomy bleeding. Polyp location, size, and pathology, as well as the method of resection, were recorded. In addition, we assessed the occurrence and severity of IPPB and the need for intervention.

RESULTS

We found 239 eligible polyps in 182 patients. The mean (SD) age was 58.8 (8.3) years, and 61% were males. IPPB occurred in 72 of 239 polyps, corresponding to a per-polyp bleeding percentage of 30.1% and in 65 of 182 patients, equating to a per-patient bleeding rate of 35.7%. We successfully treated bleeding by endoscopic hemostasis in 57%; the remaining 31 polyps (43%) did not require endoscopic intervention. There was no association between IPPB with age, gender, or use of aspirin or antithrombotic agents. In the bivariate model, polyp size and pathology were not associated with the risk of IPPB. Right-sided polyps were associated with a reduced risk of IPPB in the bivariate model by 61% (odds ratio=0.39; 95% confidence interval, 0.21-0.74; P =0.0057). In the multivariate model, choking the polyp base decreased the likelihood of IPPB by 97% (odds ratio=0.03; 95% confidence interval, 0.00-0.86; P =0.0459). There were no instances of delayed bleeding, perforation, or postpolypectomy syndrome.

CONCLUSIONS

CSP can be used for resection of ≤10 mm PPs. It is associated with a lower risk of immediate bleeding than the common perception among gastroenterologists.

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.

Different endoscopic treatments for small colorectal polyps: A systematic review, pair-wise, and network meta-analysis

Background and study aims

In recent years, cold snare polypectomy (CSP) has been increasingly used for small polyps (<10 mm) instead of hot snare polypectomy (HSP). However, evidence-based research regarding the effectiveness and safety of CSP and HSP are still lacking. Additionally, for 4-10 -mm non-pedunculated polyps, the polyp removal method is still controversial. Therefore, it is clinically significant to conduct pair-wise and network meta-analyses to assess such resection methods.

Methods

We searched PubMed, Embase, and the Cochrane library for randomized controlled trials (RCTs). Only studies that involved the resection of polyps <10 mm were included. Outcomes included the complete resection rate, polyp retrieval rate, procedure-related complications, and procedure times.

Results

Overall, 23 RCTs (5,352 patients) were identified. In meta-analysis compared CSP versus HSP for polyps <10 mm, CSP showed lower complete resection rate than HSP although with no statistically significant difference [odds ratio (OR): 0.77, 95% confidence interval (CI): 0.56-1.06]. CSP showed a lower risk of major post-polypectomy complications compared to HSP (OR: 0.28, 95% CI: 0.11-0.73). In the network meta-analysis for 4-10 mm non-pedunculated polyps, HSP, and endoscopic mucosal resection (EMR) showed a higher complete resection rate than CSP (OR: 2.7, 95% CI: 1.3-9.2 vs. OR: 2.6, 95% CI: 1.0-10) but a significantly longer time than CSP (WMD: 16.55 s, 95% CI [7.48 s, 25.25 s], p < 0.001), (WMD: 48.00 s, 95% CI [16.54 s, 79.46 s], p = 0.003). Underwater CSP ranked third for complete resection with no complications.

Conclusion

For <10 mm polyps, CSP is safer than HSP, especially for patients taking antithrombotic drugs. For 4-10 mm non-pedunculated polyps, HSP, and EMR have higher complete resection rates than CSP.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022315575.

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).

Risk Factors of Delayed Bleeding After Cold Snare Polypectomy for Colorectal Polyps: A Multicenter Study

BACKGROUND

Delayed bleeding (DB) rarely occurs after cold snare polypectomy (CSP) for colorectal polyps, but no large-scale studies have investigated this. The present study evaluated the rate, characteristics, and risk factors of DB of CSP.

METHODS

We conducted a multicenter retrospective study at 10 Japanese institutions. A total of 18,007 patients underwent CSP for colorectal polyps ≤ 10 mm in size from March 2015 to September 2019, and cases of DB (DB group) were analyzed for the rate, antithrombotic drugs, polyp size, morphology, location, and risk factors. As a control, 269 non-bleeding cases (non-DB group) with 606 polyps who underwent CSP at the same 10 facilities in the 2-week study period were extracted.

RESULTS

We analyzed 26 DB cases with 28 lesions, and the total DB rate was 0.14% (26/18,007). The DB group had significantly higher rates of using antiplatelets (42.3% vs. 13.0%, p < 0.001) and anticoagulants (19.2% vs. 2.6%, p = 0.002), and significantly higher rates of polyp size ≥ 5 mm (67.9% vs. 45.2%, p = 0.015), rectal lesion (25.0% vs. 6.6%, p = 0.003), and polypoid lesion (89.3% vs. 55.3%, p < 0.001) than the non-DB group. A multivariate analysis (odds ratio; 95% confidence interval) for patient characteristics showed antiplatelet use (4.521; 1.817-11.249, p = 0.001) and anticoagulant use (7.866; 20.63-29.988, p = 0.003) as independent risk factors for DB. Polyp size ≥ 5 mm (3.251; 1.417-7.463, p = 0.005), rectal lesion (3.674; 1.426-9.465, p = 0.007), and polypoid lesion (7.087; 20.81-24.132, p = 0.002) were also risk factors for lesion characteristics.

CONCLUSIONS

The rate of DB was 0.14% and antithrombotic drug use, polyp size, location, and morphology were related to it.

Hemostasis using purse-string reefing with endoscopic clip and endoloop for a huge hematoma after cold snare polypectomy

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Snare devices with thinner loop wire may provide higher performance for cold snare polypectomy in an experimental model

Background and study aims  Snare devices play an important role in treatment of intestinal polyps. However, there are no objective measurements for the characteristics of the various types of snare devices. Materials and methods  Seven types of snare devices from four manufacturers were evaluated based on original measurements. The evaluated factors were stiffness, cutting quality, and change in force required for cutting depending on sheath shape. The latter two factors were evaluated by measuring the force required to cut 20 % gelatin cylinders, which simulated intestinal polyps. The cutting sharpness was evaluated by observing the sectional surface of cut gelatin cylinders using a stereomicroscope. The correlations between these measurements and characteristics of the snare devices were investigated. Results  A strong positive correlation, with an R 2 value of 0.863, was shown between the force required to cut gelatin cylinders and loop wire diameter. Loop wire diameter also had a strong correlation, with an R 2 value of 0.7997, with the change in force required for cutting gelatin cylinders depending on sheath shape. No correlations were detected between loop stiffness and characteristics of snare devices. The edge-enhanced image revealed that the rougher surfaces of the gelatin cylinders were cut by snares with a thicker diameter. Conclusions  Thinner loop wire may provide higher performance in cold snare polypectomy in an experimental model.

Quality Indicators for the Detection and Removal of Colorectal Polyps and Interventions to Improve Them

Modifiable risk factors for postcolonoscopy colorectal cancer include suboptimal lesion detection (missed neoplasms) and inadequate lesion removal (incomplete polypectomy) during colonoscopy. Competent detection and removal of colorectal polyps are thus fundamental to ensuring adequate colonoscopy quality. Several well-researched quality metrics for polyp detection have been implemented into clinical practice, chief among these the adenoma detection rate. Less data are available on quality indicators for polyp removal, which currently include complete resection rates and skills assessment tools. This review summarizes the available literature on quality indicators for the detection and removal of colorectal polyps, as well as interventions to improve them.

Comparison of cold biopsy forceps vs cold snare for diminutive colorectal polyp removal: A multicenter non-inferiority randomized controlled trial

BACKGROUND

European guidelines recommends the use of cold snare polypectomy (CSP) for removal of diminutive colorectal polyps (DCP). However, for DCP < 4 mm cold biopsy forceps (CBF) may be optional. We aimed to compare the efficacy of CSP with CBF for removal of DCP in routine colonoscopy.

METHODS

We conducted a multicenter non-inferiority randomized controlled trial. After screening, 123 patients were prospectively included and 180 DCPs were removed by either CBF or CSP after randomization (1:1). The primary end-point was the histological complete resection rate defined by negative additional biopsies taken from the edge of the polypectomy ulcer site.

RESULTS

Among DCPs, 121 (67.2%) adenomas or sessile serrated lesions were considered for the analysis. Polyps were 4 [1-5] mm in size, mostly flat (55.4%) and located in the proximal colon (44.6%). The en bloc resection rate was higher in the CSP group than the CBF group (91.7% vs. 42.6%, p < 0.001). The histological complete resection rate was comparable in the two groups (93.33% vs 90.16%; p = 0.527), even for polyps < 4 mm (91.30% vs 91.30%; p = 1). All specimens were retrieved and there was no difference in terms of procedure times and adverse events. Finally, univariate analysis did not identify any potential factor associated with complete resection rate.

CONCLUSION

In this study, CSP was comparable to CBF for the removal of DCP. Therefore, CBF may be considered as an alternative technique for resection of DCP, together with CSP, ClinicalTrials.gov registry (NCT04727918).

Recurrence rate and lesions characteristics after cold snare polypectomy of high-grade dysplasia and T1 lesions: A multicenter analysis

BACKGROUND AND AIM

High-grade dysplasia (HGD) and T1 lesions are accidentally resected by cold snare polypectomy (CSP) and the characteristics, and follow-up of them has not been reported. In this study, we analyzed the histopathological findings and recurrence of them.

METHODS

This was a multicenter retrospective-cohort study. We collected HGD and T1 lesions of ≤ 10 mm resected by CSP among 15 520 patients receiving CSP from 2014 to 2019 at nine related institutions, and we extracted only cases receiving definite follow-up colonoscopy after CSP of HGD and T1 lesions. We analyzed these tumor's characteristics and therapeutic results such as R0 resection and local recurrence and risk factors of recurrence.

RESULTS

We collected 103 patients (0.63%) and extracted 80 lesions in 74 patients receiving follow-up colonoscopy for CSP scar. Mean age was 68.4 ± 12.0, and male rate was 68.9% (51/80). The mean tumor size (mm) was 6.6 ± 2.5, and the rate of polypoid morphology and rectum location was 77.5% and 25.0%. The rate of magnified observation was 53.8%. The rates of en bloc resection and R0 resection were 92.5% and 37.5%. The local recurrence rate was 6.3% (5/80, median follow-up period: 24.0 months). The recurrence developed within 3 months after CSP for four out of five recurrent cases. Comparing five recurrent lesions to 75 non-recurrent lesions, a positive horizontal margin was a significant risk factor (60.0% vs 10.7%, P < 0.001).

CONCLUSIONS

High-grade dysplasia and T1 resected by CSP were analyzed, and the local recurrence rate of them was substantially high.

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.

Polypectomy Techniques

Polyps in the upper and lower gastrointestinal tract can be premalignant or malignant lesions that can be treated endoscopically in early stages to prevent morbidity and more invasive procedures. This article critically reviews the techniques available and provides recommendations for endoscopic polypectomy.

Dedicated Cold Snare vs. Traditional Snare for Polypectomy of Diminutive and Small Lesions in a Porcine Model: A Research Group for Endoscopic Instruments and Stents (REIS) Study

BACKGROUND/AIMS

The aim of this in vivo animal study was to evaluate the effectiveness and safety of dedicated cold snare (DCS) compared with those of traditional snare (TS) for cold snare polypectomy (CSP).

METHODS

A total of 36 diminutive (5 mm) and 36 small (9 mm) pseudolesions were made by electrocoagulation in the colons of mini-pigs.

RESULTS

For the diminutive lesions, there were no significant differences in technical success rate, procedure time, or complete resection rate between the DCS and TS groups; the rate of uneven resection margin in the DCS group was significantly lower than that of the TS group. For small lesions, technical success rate and complete resection rate were significantly higher in the DCS group than in the TS group (100% [18/18] vs. 55.6% [10/18], p=0.003; 94.4% [17/18] vs. 40% [4/10], p=0.006). In addition, the procedure duration was significantly shorter, and the rate of uneven resection margin was significantly lower in the DCS group (28.5 sec vs. 66.0 sec, p=0.006; 11.1% [2/18] vs. 100% [10/10], p<0.001). Two cases of perforation occurred in the DCS group. Multivariate analysis revealed that DCS use was independently associated with complete resection.

CONCLUSION

DCS is superior to TS in terms of technical success, complete resection, and reducing the duration of the procedure for CSP of small polyps.

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.