Tip-in endoscopic mucosal resection: Simple, efficacious trick for endoscopic mucosal resections of large colorectal polyps

Clinical outcomes and learning curve of Tip-in endoscopic mucosal resection for 15-25 mm colorectal neoplasms among non-experts

BACKGROUND AND AIM

Tip-in endoscopic mucosal resection (EMR) has a high en bloc resection rate for large colorectal neoplasms. However, non-experts' performance in Tip-in EMR has not been investigated. We investigated whether Tip-in EMR can be achieved effectively and safely even by non-experts.

METHODS

This retrospective study included consecutive patients who underwent Tip-in EMR for 15-25 mm colorectal nonpedunculated neoplasms at a Japanese tertiary cancer center between January 2014 and December 2020. Baseline characteristics, treatment outcomes, learning curve of non-experts, and risk factors of failing self-achieved en bloc resection were analyzed.

RESULTS

A total of 597 lesions were analyzed (438 by experts and 159 by non-experts). The self-achieved en bloc resection (69.8% vs 88.6%, P < 0.001) and self-achieved R0 resection (58.3% vs 76.5%, P < 0.001) rates were significantly lower in non-experts with <10 cases of experience than in experts, but not in non-experts with >10 cases. Adverse event (P = 0.165) and local recurrence (P = 0.892) rates were not significantly different between experts and non-experts. Risk factors of failing self-achieved en bloc resection were non-polypoid morphology (OR 3.4, 95% CI 1.6-7.3, P = 0.001), lesions with an underlying semilunar fold (OR 3.6, 95% CI 1.6-7.3, P < 0.001), positive non-lifting sign (OR 3.1, 95% CI 1.2-8.0, P = 0.023), and non-experts with an experience of ≤10 cases (OR 3.6, 95% CI 2.1-6.3, P < 0.001).

CONCLUSION

The clinical outcomes of Tip-in EMR for 15-25 mm lesions performed by non-experts were favorable.

Tip-in EMR as an alternative to endoscopic submucosal dissection for 20- to 30-mm nonpedunculated colorectal neoplasms

BACKGROUND AND AIMS

Tip-in EMR, which includes anchoring the snare tip, has recently shown a favorable en-bloc and R0 resection rate for colorectal neoplasms. Thus, Tip-in EMR may be an alternative to endoscopic submucosal dissection (ESD). We aimed to compare clinical outcomes between Tip-in EMR and ESD for large colorectal neoplasms.

METHODS

This retrospective study evaluated consecutive patients who underwent Tip-in EMR or ESD for 20- to 30-mm nonpedunculated colorectal neoplasms at a Japanese tertiary cancer center between January 2014 and December 2019. Baseline characteristics, treatment results, and long-term outcomes were analyzed using 1:1 propensity score matching.

RESULTS

Seven hundred nine lesions were evaluated. The Tip-in EMR group included 1 lesion with a nonlifting sign but no lesions with fold convergence. After propensity score matching, each group included 140 lesions. The ESD group showed significantly higher en-bloc resection rates (99.3% vs 85.0%) and R0 resection rates (90.7% vs 62.9%). Procedure time was significantly shorter in the Tip-in EMR group (8 minutes vs 60 minutes). The Tip-in EMR and ESD groups did not differ significantly with respect to local recurrence rate (2.1% vs 0%).

CONCLUSIONS

Tip-in EMR is comparable with ESD with respect to the local recurrence rate but has a shorter procedure time, despite the lower en-bloc and R0 resection rates for 20- to 30-mm nonpedunculated colorectal neoplasms without fold convergence or nonlifting sign. Thus, Tip-in EMR could be a feasible alternative to ESD in these lesions.

Modified endoscopic mucosal resection techniques for treating precancerous colorectal lesions

Endoscopic mucosal resection (EMR) is a technique allowing efficacious and minimally invasive resection of precancerous lesions across the entire gastrointestinal tract. However, conventional EMR, involving injection of fluid into the submucosal space, is imperfect, given the high rate of recurrence of post-endoscopic resection adenoma, especially after piecemeal resection. In light of these observations, modifications of the technique have been proposed to overcome the weakness of conventional EMR. Some of them were designed to maximize the chance of en bloc resection-cap-assisted EMR, underwater EMR, tip-in EMR, precutting, assisted by ligation device-while others were designed to minimize the complications (cold EMR). In this review, we present their modes of action and summarize the evidence regarding their efficacy and safety.

Tip-in Endoscopic Mucosal Resection for 15- to 25-mm Colorectal Adenomas: A Single-Center, Randomized Controlled Trial (STAR Trial)

INTRODUCTION

One-piece endoscopic mucosal resection (EMR) for lesions >15 mm is still unsatisfactory, and attempted 1-piece EMR for lesions >25 mm can increase perforation risk. Therefore, modifications to ensure 1-piece EMR of 15- to 25-mm lesions would be beneficial. The aim of this study was to investigate whether Tip-in EMR, which anchors the snare tip within the submucosal layer, increases en bloc resection for 15- to 25-mm colorectal lesions compared with EMR.

METHODS

In this prospective randomized controlled trial, patients with nonpolypoid colorectal neoplasms of 15-25 mm in size were recruited and randomly assigned in a 1:1 ratio to undergo Tip-in EMR or standard EMR, stratified by age, sex, tumor size category, and tumor location. The primary endpoint was the odds ratio of en bloc resection adjusted by location and size category. Adverse events and procedure time were also evaluated.

RESULTS

We analyzed 41 lesions in the Tip-in EMR group and 41 lesions in the EMR group. En bloc resection was achieved in 37 (90.2%) patients undergoing Tip-in EMR and 30 (73.1%) who had EMR. The adjusted odds ratio of en bloc resection in Tip-in EMR vs EMR was 3.46 (95% confidence interval: 1.06-13.6, P = 0.040). The Tip-in EMR and EMR groups did not differ significantly in adverse event rates (0% vs 4.8%) or median procedure times (7 vs 5 minutes).

DISCUSSION

In this single-center randomized controlled trial, we found that Tip-in EMR significantly improved the en bloc resection rate for nonpolypoid lesions 15-25 mm in size, with no increase in adverse events or procedure time.