Introduction

Tip-in endoscopic mucosal resection (EMR) has shown a favorable resection outcome for large colorectal polyps.^{1, 2} However, reported outcomes have been limited to experts’ performance. To generalize the outcomes, trainees’ performance of Tip-in EMR is an interest, however, available data are absent.

Aims & Methods

To clarify whether Tip-in EMR can be achieved effectively and safely even by trainees, in this single-center retrospective study, clinical outcomes of Tip-in EMR between experts and trainees were compared. Inclusion was 15–25 mm non-pedunculated colorectal neoplasms resected by Tip-in EMR between January 2014 and December 2020. Exclusion was residual lesions after the previous resection. Data were collected from medical records and prospectively recorded endoscopy and pathology databases. Baseline characteristics, treatment results, histological outcomes, and surveillance outcomes were analyzed. In our institution, trainees perform Tip-in EMR under the supervision of experts, and switch to experts when experts decide to switch during the procedure, all of which were also analyzed as the trainee group. Independent procedure completion and independent en bloc resection were defined as achieving procedure completion and en bloc resection without switching, respectively. Failure of independent en bloc resection was defined as piecemeal resection or switching. Residual lesions were defined as endoscopically detected residuals that were pathologically confirmed as neoplasia. All procedures performed by trainees were grouped into three periods (period 1: 1–10 cases, period 2: 11–20 cases, and period 3: ≥21 cases), and the learning curve was assessed. A logistic regression analysis was performed to examine the risk factors of failure of independent en bloc resection.

Results

A total of 597 lesions (550 patients) were analyzed. Among them, 438 lesions (402 patients) and 159 lesions (148 patients) were resected by 6 experts and 14 trainees, respectively. The independent procedure completion was 146 cases (91.8%) in the trainees and 438 cases (100%) in the experts. The en bloc resection rates did not differ between trainees and experts (83.0% vs. 88.6%, P = .098). However, the independent en bloc resection rate was significantly lower in trainees (77.4% vs. 88.6%, P = .001). There was no significant difference in the incidence of adverse events (2.5% vs. 5.7%, P = .165). Among 380 lesions (63.6%) of 347 patients who received surveillance colonoscopy, 11 residual lesions were identified; 3 lesions (3.1%) in the trainees and 8 (3.5%) in the experts (P = 1), all of them were removed endoscopically. For the learning curve of trainees, the independent en bloc resection (OR 3.4, 95%CI 2.0–5.7, P < .001) was significantly lower and took longer procedure time (median 8.6 min vs. 5.8 min, P < .001) in period 1 than those of experts, but not in period 2 and 3. In multivariate analysis, risk factors of failure of independent en bloc resection were non-polypoid morphology (OR 3.4, 95% CI: 1.6–7.3; P = .001), positive non-lifting signs (OR 3.1, 95%CI: 1.2–8.0; P = .023), lesions with an underlying semilunar fold (OR 3.6, 95%CI: 2.0–6.3; P < .001), and trainees with experience ≤10 procedures (OR 3.6, 95%CI: 2.1-6.3, P<.001).

Conclusion

We demonstrated favorable outcomes of Tip-in EMR for 15-25 mm lesions performed by trainees. However, Tip-in EMR should be performed under the supervision of experts, especially for trainees with experience of ≤10 cases.

References

1. Imai K, Hotta K, Ito S, et al. Tip-in Endoscopic Mucosal Resection for 15- to 25-mm Colorectal Adenomas: A Single-Center, Randomized Controlled Trial (STAR Trial). Am J Gastroenterol. 2021;116:1398-1405.
2. Takada K, Hotta K, Imai K, et al. Tip-in EMR as an alternative to endoscopic submucosal dissection for 20- to 30-mm nonpedunculated colorectal neoplasms. Gastrointestinal Endosc. 2022;96:849-856.

Introduction

Hot snare polypectomy (HSP) has been commonly applied for 10-19 mm polyps. The incidence of delayed bleeding after HSP for 10-19 mm is reported to be 2.1-2.8% [1-2], which is not negligible and expected to be higher in cases with antithrombotic drug use. Blended or coagulation currents are commonly used for HSP, but the coagulation current causes thermal injury to the deeper submucosal layer including larger vessels, resulting in a risk for delayed bleeding [3]. Cold snare polypectomy (CSP) reduces the risk for delayed bleeding compared with HSP [4], but CSP for colorectal polyps 10-19 mm is unsatisfactory for its higher rates of incomplete resection, leading to a higher incidence of local recurrence [5]. We hypothesized that low-power pure cut current (LPPC) without coagulation current can decrease thermal injury and conducted a phase I study assessing the feasibility of LPPC HSP for 10-14 mm adenoma (UMIN Clinical Trials Registry; UMIN000037678). Although there was no delayed bleeding among 90 patients with 100 polyps, sample size was insufficient to assess the safety of LPPC HSP.

Aims & Methods

This study aimed to evaluate the safety of LPPC HSP for colorectal neoplasms. In this multicenter, retrospective, observational study, consecutive patients who underwent LPPC HSP for nonpedunculated colorectal neoplasms 10-14 mm at two Japanese institutions between December 2018 and March 2022 were evaluated. Data were collected from medical records and prospectively recorded databases of endoscopic and pathologic findings. LPPC HSP was performed using a 10-mm or 15-mm thin hexagonal snare with either of the following modes; PureCut, effect 1, 10W (ESG-300), Autocut, effect 1, 10 W (VIO300D), or Autocut, effect 0.4 (VIO3). We analyzed the treatment outcomes of LPPC HSP. We also compared the delayed bleeding rate of LPPC HSP with the historical control of HSP, which was set as 2.1% (55/2629) based on the previous meta-analysis [1], and calculated the power value using a one-sample proportion test.

Results

A total of 339 patients with 410 lesions sized 10-14 mm were identified. The en bloc and R0 resection rates were 94.9% and 86.7%, respectively. Immediate bleeding requiring hemostasis developed in 4 lesions (1.0%). No perforation developed. Delayed bleeding developed in two patients, both of them required hospital admissions but were conservatively managed without endoscopic hemostasis or blood transfusion. Delayed bleeding rate was 0.6% per patient (2/339). LPPC-HSP was associated with a 71.4% reduction in the risk of delayed bleeding compared to the historical control (2.1%), with a power of 80.4% using a 2-sided significance level of 0.1.

Table. Baseline characteristics and treatment outcomes of low-power pure cut hot snare polypectomy

Conclusion

Delayed bleeding rate of LPPC HSP for nonpedunculated colorectal neoplasms 10-14 mm was 0.6%, which may be lower than conventional HSP. A large prospective study is warranted to assess the safety of LPPC HSP.

References

1. Nishizawa T, Suzuki H, Goto O, et al. Effect of prophylactic clipping in colorectal endoscopic resection: A meta-analysis of randomized controlled studies. United European Gastroenterol J 2017;5:859-867.
2. Matsumoto M, Kato M, Oba K, et al. Multicenter randomized controlled study to assess the effect of prophylactic clipping on post-polypectomy delayed bleeding. Dig Endosc 2016;28:570-576
3. Takayanagi D, Nemoto D, Isohata N, et al. Histological Comparison of Cold versus Hot Snare Resections of the Colorectal Mucosa. Dis Colon Rectum 2018;61:964-970.
4. Chang LC, Chang CY, Chen CY, et al. Cold Versus Hot Snare Polypectomy for Small Colorectal Polyps: A Pragmatic Randomized Controlled Trial. Ann Intern Med 2023;176:311-319.
5. Djinbachian R, Iratni R, Durand M, et al. Rates of Incomplete Resection of 1- to 20-mm Colorectal Polyps: A Systematic Review and Meta-Analysis. Gastroenterology 2020;159:904-914.e12.

Introduction

The risk factors for synchronous lymph node metastasis (LNM) in pT1 colorectal cancer (CRC) are submucosal invasion depth (≥1000µm), lymphovascular involvement (LVI), poorly differentiated components (por), and tumor budding (BD). On the other hand, in pedunculated lesions with invasion confined to the head of the polyp, the incidence of LNM and recurrence have been reported to be very low (0-2.4% and 0%, respectively).^1,2 However, the robust evidence has been limited.

Aims & Methods

This retrospective study aimed to compare the incidence of LNM and recurrence between the head and stalk invasion groups, based on submucosal invasion assessment using Haggitt Level 2 (HL2; the junction line between normal and neoplastic epithelium), and to evaluate the impact of LNM/recurrence risk factors in pedunculated pT1 CRC.
Patients with pedunculated pT1 CRC treated by endoscopic or surgical resection in our hospital between January 2010 and December 2021 were included. Those with multiple invasive CRCs, synchronous advanced cancer in other organs, and familial adenomatous polyposis were excluded. The submucosal invasion was classified into two groups, head invasion (above HL2) and stalk invasion (beyond HL2). Clinicopathological characteristics, incidence of LMN, and recurrence rate were analyzed between patients with head and stalk invasion.

Results

The study included 66 patients with 66 lesions. The median age was 67 years, and 52 patients (78.8%) were male. The median tumor size was 20mm, and the location was as follows: 4 lesions (6.1%) in the right colon and 62 lesions (93.9%) in the left colon. There were 40 head invasion and 26 stalk invasion lesions. There were no significant differences between the two groups for LVI (17.5% vs 26.9%), por (2.5% vs 7.5%), and BD (5.0% vs 7.7%). Surgical resection was performed more frequently in the stalk invasion group (20% vs 77%, P < 0.01). Synchronous LNM was observed in 2 patients in the head invasion group (5.0%, 95% confidence interval [CI] 0.6-16.9), and 1 patient in the stalk invasion group (3.8%, 95%CI 0.1-19.6) (P = 1). Recurrence was observed in 1 patient in the head invasion group (2.5%, 95%CI 0.1-13.2), and 1 patient in the stalk invasion group (3.8%, 95%CI 0.1-19.6) (P = 1), both of them were distant metastasis. In patients without LVI, por, nor BD, there was no LMN in either group, but recurrence was observed in 1/32 patients in the head invasion group (3.1%, 95%CI 0-17.1), and 1/16 patients in the stalk invasion group (6.3%, 95%CI 0-30.3) (P = 0.61). The patient with recurrence in the head invasion group without LVI/por/BD revealed multiple liver metastases one year after endoscopic resection, and he received chemotherapy but died of colon cancer one and a half years after recurrence.

Conclusion

In pedunculated pT1 CRC, synchronous LNM and recurrence were observed in the head invasion group, with no significant difference from the stalk invasion group. Among cases without LVI/por/BD, there was no LNM but recurrence was observed in both of head and stalk invasion groups. Contrary to the previous reports, head invasion was not a completely LNM/recurrence-free condition, so endoscopic resection alone cannot be considered curative.

References

1. Matsuda T, et al. Risk of lymph node metastasis in patients with pedunculated type early invasive colorectal cancer: A retrospective multicenter study, Cancer Sci. 2022;102:1693-1697.
2. Asayama N, et al. Long-term outcomes after treatment for pedunculated-type T1 colorectal carcinoma: a multicenter retrospective cohort study, J Gastroenterol. 2016;51:702-710.

Introduction

Endoscopic mucosal resection (EMR) is standard of care for the management of large (≥20mm) non-pedunculated colonic polyps (LNPCPs). Its efficacy and cost effectiveness were limited by recurrence. Margin thermal ablation (MTA) to the post-EMR defect, has greatly mitigated this problem. However, electrocautery-related complications of delayed bleeding and perforation incur significant morbidity.
Cold snare polypectomy is effective and safe for the resection of small polyps with negligible recurrence rates. Application of cold snare resection to LNPCPs, while an attractive alternative, lacks high-quality evidence. We conducted a randomized trial to compare the efficacy and safety of cold EMR (C-EMR) to conventional (H-EMR).

Aims & Methods

A prospective single-centre randomized controlled trial was conducted at an Australian tertiary referral centre for flat, 15-50mm adenomatous LNPCPs referred for endoscopic resection. Prior to resection, eligible LNPCPs were randomly assigned to EMR using a dedicated cold snare or conventional H-EMR with margin thermal ablation (control). First surveillance colonoscopy (SC1) was conducted 6 months following resection. Scars were evaluated with high-definition white-light, narrow-band imaging and biopsy. The primary outcome was endoscopically visible and/or histologically confirmed recurrence at SC1. Secondary outcomes were clinically significant post-EMR bleeding (CSPEB), delayed perforation and technical success.

Results

931 LNPCPs were referred for endoscopic resection between November 2019-September 2023. 177 LNPCPs in 177 patients were randomized to either the C-EMR arm (n=87) or H-EMR arm (n=90). Treatment groups were equivalent with no significant difference in lesion size or technical success (86/87 (98.9%) vs 90/90 (100%); p=0.31). One C-EMR required conversion to H-EMR due to unexpected submucosal fibrosis. Following exclusions, 146 LNPCPs undertook SC1 (76 C-EMR, 70 H-EMR). 5 patients await surveillance. On intention to treat and per protocol analysis, recurrence was significantly greater in C-EMR (16/87, 18.4% vs 1/90, 1.1%; p<0.001 and 16/76, 21.1% vs 1/70, 1.4%; p<0.001 respectively). Significant deep mural injury (27/90 (30%) vs 0; p<0.001) and delayed perforation (1/90 (1.1%) vs 0; p=0.32) only occurred in the H-EMR group. CSPEB and intraprocedural bleeding were significantly greater in the H-EMR arm (7/90 (7.8%) vs 1/87 (1.1%); p = 0.034 and 12/90 (13.3%) vs C-EMR arm 1/87 (1.1%); p=0.002 respectively).

Conclusion

Compared to conventional 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.

Disclosure

Michael Bourke: Research Support: Olympus Medical, Cook Medical, Boston Scientific
The remaining authors have no financial, professional, or personal conflicts of interest to disclose

Introduction

Colorectal endoscopic mucosal resection (EMR) is the treatment of choice for large colorectal lesions, but it has an important recurrence risk, requiring endoscopic surveillance. This study aims to identify factors associated with relapse and complications, by analysing the 5-year follow-up.

Aims & Methods

Prospective cohort study conducted in a single centre, including all patients submitted to colorectal pEMR between 2009 and 2021 with follow-up ≥3 months. We analysed lesion characteristics, calculated Sydney EMR recurrence tool (SERT) and SMSA (size, morphology, site, access) scores and compared complication and recurrence rates and respective risk factors.

Results

Included 568 mucosal resections, median age 69.5 years (IQR 62.3-76.0), male sex 58.1%. From the lesions included: 32.6% ≥40mm; 51.6% plane and 48.4% sessile; 35.9% in the right colon, 27.6% in the rectum, 23.2% in the transverse colon and 13.2% in the left colon. The median SMSA score was 4 (IQR 3-4) and median SERT score 1 (IQR 0-2), complication rate of 7.0% (bleeding, n=33; perforation, n=4; post-polypectomy syndrome, n=3) and overall recurrence rate of 20.3%: 15.1% in 3 months, 6.3% in 12 months, 2.5% in 36 months and 0% in 60 months.
The variables associated with recurrence were size ≥40mm (35.0% vs. 14.6%, p<0.001), anal location (35.1% vs. 19.7%, p<0.01), SERT score>0 (27.5% vs. 11.8%, p<0.001) and SMSA score=4 (30.6% vs. 11.5%, p<0.001), but not argon plasma therapy (22.8% vs. 18.7%, p=0.26). By logistic regression, size ≥40mm was associated with higher recurrence, but not statistically significant (OR 3.19, CI95% 0.69-1.63).
Use of anticoagulant/antiplatelet drugs was associated with higher risk of complications (12.7% vs. 4.7%, p<0.001), particularly bleeding (11.4% vs. 4.2%, p<0.01), with no difference for size ≥40mm (9.2% vs. 6.0%, p=0.17) or SMSA score=4 (7.6% vs. 6.5%, p=0.61).

Conclusion

The 5-year surveillance proved colorectal EMR’s efficacy. Recurrence is higher in lesions ≥40mm, with anal location, SERT score>0 and SMSA score=4, whereas bleeding is more frequent with the use of anticoagulant/antiplatelet drugs.

Introduction

Endoscopic mucosal resection (EMR) of large (>/-20mm) non-pedunculated colorectal polyps (LNPCP) </- 40mm is associated with an increased risk of recurrent or residual adenoma (RRA). Margin Thermal Ablation to the EMR defect margin using snare-tip soft coagulation (MTA) reduces the rate of RRA. We sought to analyse its effect in a large prospective cohort of LNPCP >/-40mm.

Aims & Methods

We retrospectively analysed a prospectively collected cohort of consecutive patients who underwent EMR in an expert tissue resection centre. MTA technique was developed in 2012. Enrolment for the MTA randomised control occurred between July 2013-May 2016 and became standard practice from mid-2017. The cohort was divided into three phases: ‘pre-MTA’; April 2008- June 2012, ‘MTA adoption’; July 2012-June 2017 and ‘standardised MTA’; July 2017-April 2023. The primary outcome was to compare the RRA rate between the three time periods.

Results

Over 15 years until April 2023, 973 LNPCP >/-40mm in 973 patients underwent EMR (median lesion size 50mm, IQR 20mm) of which 893 (92%) were successful. 824 patients (median lesion size 50mm, IQR 20) underwent SC1 (median of 6 months [IQR 4]). The rates of RRA in the pre-MTA, MTA-adoption and standardised-MTA phases were 20.3% (n=45/221), 19.1% (n=59/309) and 4.4% (n=13/294) respectively (p=<0.001). The rates of complete MTA in the pre-MTA, MTA adoption and standardised-MTA phases were 0, 38.2% (n=118/309) and 93.9% (n=276/294). 18 (6.1%) of cases within the standardised-MTA did not receive MTA due to difficult access (n=7), concern for stricture formation in fully circumferential LNPCP (n=9) or sedation-related issues (n=2). The rate of RRA in this group was 22.2% (n=4/18).

Conclusion

MTA post-EMR of LNPCP >/-40mm (median size 50mm) significantly reduced the rate of RRA in a large, prospective cohort. When MTA was not applied, RRA was similar across the three time periods (p=0.1), indicating that the main impact on RRA reduction was the use of MTA with snare-tip soft coagulation, rather than a factor of EMR technique improvement over time.