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

Incomplete resection of colorectal polyps of 4-20 mm in size when using a cold snare, and its associated factors

BACKGROUND : Cold snare polypectomy (CSP) is increasingly used for polypectomy and is recommended as the first-line modality for small (< 10 mm) polyps. This study aimed to evaluate incomplete resection rates (IRRs) when using CSP for colorectal polyps of 4-20 mm. METHODS : Adults (45-80 years) undergoing screening, surveillance, or diagnostic colonoscopy and CSP by one of nine endoscopists were included. The primary outcome was the IRR for colorectal polyps of 4-20 mm, defined as the presence of polyp tissue in marginal biopsies after resection of serrated polyps or adenomas. Secondary outcomes included the IRR for serrated polyps, ease of resection, and complications. RESULTS:  413 patients were included (mean age 63; 48 % women) and 182 polyps sized 4-20 mm were detected and removed by CSP. CSP required conversion to hot snare resection in < 1 % of polyps of < 10 mm and 44 % of polyps sized 10-20 mm. The IRRs for polyps < 10 mm and ≥ 10 mm were 18 % and 21 %. The IRR was higher for serrated polyps (26 %) compared with adenomas (16 %). The IRR was higher for flat (IIa) polyps (odds ratio [OR] 2.9, 95 %CI 1.1-7.4); and when resection was judged as difficult (OR 4.2, 95 %CI 1.5-12.1), piecemeal resection was performed (OR 6.6, 95 %CI 2.0-22.0), or visible residual polyp was present after the initial resection (OR 5.4, 95 %CI 2.0-14.9). Polyp location, use of a dedicated cold snare, and submucosal injection were not associated with incomplete resection. Intraprocedural bleeding requiring endoscopic intervention occurred in 4.7 %. CONCLUSIONS : CSP for polyps of 4-9 mm is safe and feasible; however, for lesions ≥ 10 mm, CSP failure occurs frequently, and the IRR remains high even after technical success. Incomplete resection was associated with flat polyps, visual residual polyp, piecemeal resection, and difficult polypectomies.

Recurrence rates after endoscopic resection of large colorectal polyps: A systematic review and meta-analysis

BACKGROUND

Complete polyp resection is the main goal of endoscopic removal of large colonic polyps. Resection techniques have evolved in recent years and endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR) with margin ablation, cold snare polypectomy (CSP), cold EMR, and underwater EMR have been introduced. Yet, efficacy of these techniques with regard to local recurrence rates (LRRs) vs traditional hot snare polypectomy and standard EMR remains unclear.

AIM

To analyze LRR of large colonic polyps in a systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE, EBM Reviews, and CINAHL were searched for prospective studies reporting LRR or incomplete resection rate (IRR) after colonic polypectomy of polyps ≥ 10 mm, published between January 2011 and July 2021. Primary outcome was LRR for polyps ≥ 10 mm.

RESULTS

Six thousand nine hundred and twenty-eight publications were identified, of which 34 prospective studies were included. LRR for polyps ≥ 10 mm at up to 12 mo’ follow-up was 11.0% (95%CI, 7.1%-14.8%; 15 studies; 4904 polyps). ESD (1.7%; 95%CI, 0%-3.4%; 3 studies, 221 polyps) and endoscopic mucosal resection with margin ablation (3.3%; 95%CI, 2.2%-4.5%; 2 studies, 947 polyps) significantly reduced LRR vs standard EMR without (15.2%; 95%CI, 12.5%-18.0%; 4 studies, 650 polyps) or with unsystematic margin ablation (16.5%; 95%CI, 15.2%-17.8%; 6 studies, 3031 polyps).

CONCLUSION

LRR is significantly lower after ESD or EMR with routine margin ablation; thus, these techniques should be considered standard for endoscopic removal of large colorectal polyps. Other techniques, such as CSP, cold EMR, and underwater EMR require further evaluation in prospective studies before their routine implementation in clinical practice can be recommended.

Randomized controlled trial investigating use of submucosal injection of EverLift™ in rates of complete resection of non-pedunculated 4-9 mm polyps

INTRODUCTION

Currently, cold snare polypectomy (CSP) without submucosal injection is recommended for removing polyps < 10 mm. Use of viscous submucosal agents has not been previously evaluated in CSP. We investigate the potential role of EverLift™ (GI Supply, Pennsylvania) in CSP.

METHODS

The study is a single-center prospective randomized non-inferiority clinical trial evaluating CSP of non-pedunculated 4-9 mm polyps, with or without submucosal injection of EverLift™. Patients 18-80 years of age presenting for colonoscopy were recruited. Eligible polyps underwent block randomization to CSP with or without EverLift™. Following CSP, two biopsies were performed at the CSP site margin. The primary non-inferiority outcome was complete resection rate, defined by absence of residual polyp in the margin biopsies (non-inferiority margin -10%).

RESULTS

A total of 291 eligible polyps underwent CSP, with 142 removed using EverLift™. There was similar polyp size and distribution of pathology between the two groups. Overall, there was a low rate of positive margins with (1.4%) or without submucosal injection (2.8%), with no significant difference in complete resection (difference 1.28%, 95% CI: -2.66 to 5.42%), demonstrating non-inferiority of EverLift™ injection. Use of EverLift™ significantly increased CSP time (109.8 vs 38.8 s, p < 0.0001) and frequency of use of hemostatic clips (13.4 vs 3.6%, p = 0.002).

CONCLUSION

Submucosal injection of EverLift™ was non-inferior to CSP of 4-9 mm polyps without injection and increased time for resection as well as use of hemostatic clips to control acute bleeding. Our results suggest that polypectomy of 4-9 mm polyps can be safely performed without submucosal injection of EverLift™.

Effectiveness and safety of the different endoscopic resection methods for 10- to 20-mm nonpedunculated colorectal polyps: A systematic review and pooled analysis

BACKGROUND

We performed a systematic review and pooled analysis to assess the effectiveness and safety of different endoscopic resection methods for 10- to 20-mm nonpedunculated colorectal polyps.

METHODS

Articles in PubMed, EMBASE, and the Cochrane Library related to the common endoscopic treatment of 10- to 20-mm nonpedunculated polyps published as of April 2020 were searched. Primary outcomes were the R0 resection rate and en bloc resection rate. Secondary outcomes were safety and the recurrence rate. Meta-regression and subgroup analysis were also performed.

RESULTS

A total of 36 studies involving 3212 polyps were included in the final analysis. Overall, the effectiveness of resection methods with a submucosal uplifting effect, including endoscopic mucosal resection (EMR), cold EMR and underwater EMR (UEMR), was better than that of methods without a nonsubmucosal uplifting effect [R0 resection rate, 90% (95% confidence interval (CI) 0.81-0.94, I² = 84%) vs 82% (95% CI 0.78-0.85, I² = 0%); en bloc resection rate 85% (95% CI 0.79-0.91, I² = 83%) vs 74% (95% CI 0.47-0.94, I² = 94%)]. Regarding safety, the pooled data showed that hot resection [hot snare polypectomy, UEMR and EMR] had a higher risk of intraprocedural bleeding than cold resection [3% (95% CI 0.01-0.05, I² = 68%) vs 0% (95% CI 0-0.01, I² = 0%)], while the incidences of delayed bleeding, perforation and post-polypectomy syndrome were all low.

CONCLUSIONS

Methods with submucosal uplifting effects are more effective than those without for resecting 10- to 20-mm nonpedunculated colorectal polyps, and cold EMR is associated with a lower risk of intraprocedural bleeding than other methods. Additional research is needed to verify the advantages of these methods, especially cold EMR.

Computational Fluid Dynamics (CFD)-Based Optimization of Injection Process during Endoscopic Mucosal Therapy

Creation of a submucosal plane to separate the lesion from the deeper muscle layer in gastrointestinal tract is an integral and essential part of endoscopic resection therapies such as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). Thereby, an optimized submucosal injection technique is required to ensure a successful process. In this study, the computational fluid dynamics (CFD) technique is employed as a foundational step towards the development of a framework that can provide useful directions to optimize the injection process. Three different lifting agents, including Glycerol, Eleview^®, and ORISE^® gel have been used for this study. The role of different injection angles, injection dynamics, and effect of temperature are studied to understand the lifting characteristic of each agent. The study shows that Eleview^® provides the highest lifting effect, including the initial injection period. To evaluate the impact of the injection process, two cases are simulated, termed static injection and dynamic injection. Under static injection, the injection angle is investigated from lower to higher angles of injection. In the dynamic injection, two cases are modulated, where a continuous change of injection angle from lower to higher degrees (denoted as clockwise) and vice-versa in the anti-clockwise direction are investigated. Increased lifting characteristics are observed at decreasing/lower angle of injection. Further, the correlation between temperature of the lifting agents and their lifting characteristics is investigated.

Rates of Incomplete Resection of 1- to 20-mm Colorectal Polyps: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Incomplete resection of neoplastic colorectal polyps can result in postcolonoscopy colorectal cancer. We performed a systematic review and meta-analysis to determine the incomplete resection rate (IRR) of colorectal polyps and associated factors.

METHODS

We searched MEDLINE, EMBASE, EBM Reviews, and CINAHL to identify full-text articles that reported IRRs of polyps 1 to 20 mm, published until March 2019. Exclusion criteria were studies of inflammatory bowel disease cohorts, referrals for difficult polypectomy, polyp sizes larger than 20 mm, and endoscopic submucosal resection and/or dissection as polypectomy approaches. IRRs were calculated based on findings from biopsies taken at polypectomy sites or assessments of margins of resected polyps. The primary outcome was IRR for snare removal of polyps 1 to 20 mm. Secondary outcomes included IRR for polyps 1 to 10 mm and 10 to 20 mm, IRR for hot and cold snare removal of polyps 1 to 10 mm and 10 to 20 mm, IRR of snare removal with or without submucosal injection, and IRR for forceps and cold snare removal of polyps 1 to 5 mm.

RESULTS

We identified 6148 reports and used 32 studies, with a total of 9282 polyps, in our quantitative analysis. The IRR for snare removal of polyps 1 to 20 mm was 13.8% (95% confidence interval [CI] 10.3-17.3; 13 studies, 5128 polypectomies). IRRs were 15.9% for snare removal of polyps 1 to 10 mm (95% CI 9.6-22.1; 9 studies, 2531 polypectomies) and 20.8% for snare removal of polyps 10 to 20 mm (95% CI 12.9-28.8; 6 studies, 412 polypectomies). The IRR for hot snare removal of polyps 1 to 10 mm was 14.2% (95% CI 5.2-23.2) vs 17.3% for cold snare polypectomy (95% CI 14.3‒20.3). The IRR for forceps removal of polyps 1 to 5 mm was 9.9% (95% CI 7.1-13.0) vs 4.4% for snare polypectomy (95% CI 2.9-6.1).

CONCLUSIONS

In a systematic review and meta-analysis, we found that colorectal polyps 1 to 20 mm are frequently incompletely resected, and that risk increases for polyps 10 mm or larger. There is no difference in IRRs of cold vs hot snares for polyps 1 to 10 mm. Snare polypectomy should be used over forceps for polyps 1 to 5 mm.