Short‐ and Long‐Term Outcomes of Endoscopic Resection for Serrated Lesions in Patients With Ulcerative Colitis: A Retrospective Exploratory Study

OBJECTIVES: Endoscopic resection (ER) is well established for serrated lesions in patients with noninflammatory bowel disease; however, limited evidence supports its outcomes in patients with ulcerative colitis (UC). We evaluated the short- and long-term outcomes of ER for serrated polyps in patients with UC and assessed the risk of metachronous UC-associated neoplasia (UCAN). METHODS: We retrospectively analyzed 127 patients with UC who underwent ER for colorectal neoplasms between 2004 and 2024. Serrated polyps were categorized as sessile serrated lesions (SSLs), traditional serrated adenomas (TSAs), or unclassified serrated adenomas (USAs). Short-term outcomes, including en bloc and R0 resection rates, were compared between UCAN and sporadic neoplasia (SN). Long-term outcomes, including metachronous UCAN, were also analyzed. RESULTS: Among the 127 patients, 25 serrated lesions (13 SSLs, eight TSAs, and four USAs) were identified. The en bloc and R0 resection rates for serrated lesions were 96% and 92%, respectively, comparable to those for UCAN and SN. Over a median follow-up of 68 months, one patient with TSA developed invasive cancer 34 months post-ER, and two patients with USA developed UC-associated dysplasia. No metachronous UCAN was observed in the patients with SSL. The 5-year cumulative UCAN occurrence rate in the serrated lesion group was 18%, comparable to that in the UCAN group (29%) but significantly higher than that in the SN group (2%). CONCLUSIONS: Because the outcomes of ER were comparable to those of UCAN and SN, ER appears acceptable for serrated lesions in UC. However, TSA and USA may require stricter post-ER surveillance.