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.