Challenges associated with the pathological diagnosis of colorectal tumors less than 10 mm in size

Comparing underwater and conventional cold snare polypectomy for colorectal adenomas: Prospective randomized controlled trial

Background and study aims

In this study, we aimed to evaluate efficacy and safety of underwater cold snare polypectomy (UCSP) for treating colorectal adenoma.

Patients and methods

This single-center, prospective, randomized controlled trial screened patients with colorectal adenomas measuring 4 to 9 mm in diameter that were identified through colonoscopies at the Department of Gastroenterology in Jianyang People's Hospital between April 2022 and October 2023. Patients were randomly assigned to undergo UCSP or cold snare polypectomy (CSP). Both groups underwent narrow-band imaging to determine international colorectal endoscopic morphology of type 2 noncancerous lesions. Following polyp removal, biopsy specimens were collected from the base and margins to assess the completeness of resection.

Results

The study included 227 polyps from 172 patients; median sizes in the UCSP (n = 122) and CSP groups (n=105) were 5 mm and 6 mm, respectively. The R0 (96.7% vs. 86.7%; P =0.005) and muscularis mucosa resection rates (68.9% vs. 43.8%; P <0.0001) were significantly higher in the UCSP group than in the CSP group. However, operative time for the UCSP group (109.5 s; 86.8-134.3 vs. 110.0 s; 83.5-143.5 P =0.890) was not significantly longer than that for the CSP group. Neither group exhibited delayed bleeding or perforations.

Conclusions

UCSP has a high R0 rate for colorectal adenomas measuring 4 to 9 mm.

Impact of contrast dye submucosal pre-lifting on cold snare resection of small polyps: an Italian randomized observational trial

BACKGROUND/AIMS

Small polyps are the most frequently detected lesions during colonoscopy, with an incomplete resection rate of 6.8% to 15.9%. This study aimed to improve small polyp cold snare resection radicality using submucosal contrast dye pre-lifting (PL+CSP).

METHODS

This single-center, prospective, randomized controlled trial compared the standard cold snare polypectomy technique (PL-CSP) with PL+CSP to evaluate endoscopic and histological complete resection rates, adverse events, procedural times, and polyp retrieval failure rates.

RESULTS

In 143 patients consecutively enrolled, 186 small polyps were detected and randomly assigned following a 1:1 ratio to the PL-CSP (n=97, 51.6%) and PL+CSP (n=90, 48.4%) techniques. Endoscopic (p=0.97) and histologic (p=0.23) complete resection rates did not differ significantly even in univariate analysis. The intraprocedural bleeding rate was significantly higher in the PL+CSP group as confirmed by the univariate analysis (35.8% vs. 8.3%, p<0.001). The polyps retrieval failure rates were similar (p=0.83). Procedural time was significantly longer for PL+CSP (median time, 75 vs. 45 seconds; p<0.001), without impacting colonoscopy withdrawal time (p=0.215).

CONCLUSIONS

PL+CSP of small polyps did not improve endoscopic and histological complete resection rates and polyp sample retrieval. PL+CSP had higher rates of intraprocedural bleeding and was "time-consuming".

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.

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.

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).

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.

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.

Effectiveness of suction valve button removal in retrieving resected colon polyps for better histological assessment: Propensity score matching analysis

BACKGROUND AND AIM

Fragmentation of endoscopically resected colorectal polyps during retrieval is one of the limitations for appropriate pathological diagnosis; however, little is known about steps to reduce it. We aimed to evaluate the effect of removing the suction valve button, which is one of the intricate parts of the endoscope, during polyp suction retrieval for fragmentation and pathological diagnosis.

METHODS

We retrospectively reviewed the polyps retrieved by suctioning. We used the propensity score matching method to adjust for difference between the button-attached and button-removed groups. Outcomes of fragmentation, pathological diagnosis of non-neoplastic polypectomy (NNP), and pathological cut-end among neoplastic lesions were evaluated.

RESULTS

On the basis of propensity score matching, 322 pairs of cases were selected for analysis. After matching, the difference in the variables between the two groups was closely balanced. The fragmentation rate was significantly different between the groups (button-attached 36.6% vs. button-removed 22.4%, P < 0.001). No significant difference in the NNP rate was observed between the two groups (button-attached 8.4% vs. button-removed 9.9%). The rate of unclear cut-end was lower in the button-removed group than in the button-attached group (16.2% vs. 9.1%, P = 0.010). In the multivariate analysis, button removal was independently associated with reductions of fragmentation (odds ratio [OR] 0.508, P < 0.001) and unclear cut-end (OR 0.503, P = 0.009). Also, NNP was associated with smaller lesion size (OR 0.364, P < 0.001), but not with button removal.

CONCLUSIONS

Suction valve button removal during polyp suction retrieval was an effective method to decrease the rates of fragmentation and histological unclear margins.

White light and/or magnifying endoscopy with narrow band imaging for superficial nonampullary duodenal epithelial tumors

BACKGROUND AND AIM

A reliable optical diagnosis of superficial nonampullary duodenal epithelial tumors (SNADETs) to guide optimal treatment strategy is lacking. The aim of this study was to simulate the treatment outcomes based on optical diagnosis using white light imaging (WLI) or magnifying endoscopy with narrow band imaging (MNBI) and to evaluate the method to extract optimal lesions suitable for cold snare polypectomy (CSP) or not.

METHODS

We created a decision tree model using WLI and MNBI diagnosis for ideal treatment for SNADETs. Optical diagnoses of Vienna category 3 lesions (C3), category 4/5 (C4/5) were defined based on the WLI scoring system or the MNBI pattern diagnosis. Ideal treatments were CSP for C3 < 10mm, and endoscopic mucosal resection, endoscopic submucosal dissection or surgery for lesions ≥10mm or C4/5. Ideal treatment results based on optical diagnosis were analyzed according to actual pathological results.

RESULTS

A total of 218 lesions with pre-operative diagnosis of SNADETs were included for analysis. Percentage of ideal treatment for C3 < 10mm based on WLI or MNBI or both was 88%, 83% and 97%. When WLI and MNBI diagnoses predicted the same histology, the specificity, positive predictive value and accuracy were significantly higher than those of WLI or MNBI alone (p < .05).

CONCLUSIONS

A decision tree model using lesion diameter, WLI scoring and MNBI pattern diagnosis is hypothetically useful to select ideal lesions for CSP among SNADETs. Optical diagnosis using both WLI and MNBI is more useful than WLI or MNBI alone.

Present Status of Endoscopic Submucosal Dissection for Non-Ampullary Duodenal Epithelial Tumors

Prediction of histology by endoscopic examination is important in the clinical management of non-ampullary duodenal epithelial tumors (NADETs), including adenoma and adenocarcinoma. The use of a simple scoring system based on the findings of white-light endoscopy or magnified endoscopy with narrow-band imaging is useful to differentiate between Vienna category 3 (C3) and C4/5 lesions. Less invasive endoscopic resection procedures, such as cold snare polypectomy, are quick to perform and convenient for small (<10 mm) C3 lesions. Neoplasms with higher grade histology, such as C4/5 lesions, should be treated by endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), or surgery. Although EMR often requires piecemeal resection, the complication rate is acceptable. Excellent complete resection rates could be achieved by ESD; however, it remains a challenging method considering the high risk of complications. Shielding or closure of the ulcer after ESD is effective at decreasing the risk of delayed bleeding and perforation. Laparoscopic endoscopic cooperative surgery is an ideal treatment with a high rate of en bloc resection and a low rate of complications, although it is limited to high-volume centers. Patients with NADETs could benefit from a multidisciplinary approach to stratify the optimal treatment based on endoscopic diagnoses.

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.