Background and study aims: Large (≥ 20 mm) non-pedunculated colorectal lesions have high rates of synchronous neoplasia and advanced neoplasia. Synchronous neoplasia prevalence in patients with large pedunculated lesions is uncertain. We describe synchronous neoplasia in patients with large pedunculated colorectal polyps, using a cohort of patients with large non-pedunculated lesions as controls. Patients and methods: Retrospective assessment of a prospectively recorded database listing synchronous findings in patients with ≥ 20 mm colorectal lesions referred to a tertiary center for endoscopic resection. Results: At least 1 synchronous precancerous lesion was identified in 66 of 78 (84.6%, 95% CI 74.9-91.1) patients with large pedunculated lesions and 726 of 814 (89.2%, 95% CI 87.1-91.3) patients with large non-pedunculated lesions. Patients with large pedunculated lesions had mean 4.8 synchronous conventional adenomas, and 56% had ≥ 1 synchronous high-risk lesion (advanced adenoma or advanced serrated lesion), 49% had ≥ 1 synchronous advanced conventional adenoma, and 19% had a synchronous neoplastic lesion ≥ 20 mm. Patients with large pedunculated index lesions had comparable rates of synchronous polyps, adenomas, and sessile serrated lesions, and had higher rates of synchronous adenomas with villous elements (26.9%, 95% CI 18.3-37.7 vs. 15.6%, 95% CI 13.3-18.3; p = 0.01) as well as synchronous pedunculated polyps compared to patients with non-pedunculated index lesions (33.3%, 95% CI 23.8-44.4 vs. 9.5%, 95% CI 7.6-11.7; p < 0.001). Conclusion: In patients with large (≥ 20 mm) pedunculated colorectal lesions, rates of synchronous neoplasia and advanced synchronous neoplasia are high and comparable to or higher than rates of synchronous neoplasia in patients with large (≥ 20 mm) nonpedunculated colorectal lesions.

Background and study aim The World Health Organization criteria for SPS were established in 2010 and modified in 2019. Neither set of criteria have been validated against genetic markers or proven to be the optimal criteria for defining colorectal cancer risk in patients with serrated colorectal lesions. In this study, we sought to gain insight into how frequently the change in serrated polyposis syndrome (SPS) criteria in 2019 impacted the diagnosis of SPS. Materials and methods We reviewed 279 patients with SPS diagnosed between 2010 and 2019 using the 2010 criteria (n = 163) or since 2019 using the 2019 criteria (n = 116). We reviewed whether patients in each group met the diagnosis of SPS by the alternative criteria. Results Of those diagnosed using 2010 criteria, 5.5% did not meet 2019 criteria. Of those diagnosed by 2019 criteria, 10.3% did not meet 2010 criteria. Conclusions Most patients with SPS in our database met the diagnosis of SPS by both 2010 and 2019 criteria, with only 5-10% of patients in each cohort not meeting the alternative diagnostic criteria.

Background and study aims: Live endoscopy courses are popular. The safety of performing live endoscopy has been questioned. In this study, we compared outcomes of large colorectal polyp resections during live endoscopy events (LEE) (with a small audience of 2-5 physicians) to those removed during standard procedure days (SPD) (without an audience). All procedures were performed at the endoscopist’s home unit. Methods: Retrospective assessment of the adverse event and recurrence rates for large (≥ 20 mm) non-pedunculated colorectal lesions removed during LEEs. Logistic regression was used to assess whether presence of an audience predicted worse outcomes. Results: From January 2017 to May 2021, 317 lesions were removed with a live audience and 866 were removed on SPD. Polyp pathology and procedure length were similar in both groups. There were 16 (5.0%) total adverse events in the LEE group and 30 (3.4%) in the SPD group (p = 0.224). The majority in both groups were delayed hemorrhage. There were 2 (0.6%) perforations in the LEE and 3 (0.3%) in the SPD group. Increasing polyp size was associated with more adverse events and higher recurrence. Increasing patient age predicted higher recurrence, and thermal injury of the resection margin predicted lower recurrence. There were no other predictors of adverse events or recurrence, including presence of a live audience. Conclusion: Removing large colorectal polyps with a small live audience did not increase adverse outcomes.