Efficacy and safety of endoscopic resection of appendiceal lesions. A Spanish multicenter study

AIMS: To determine the efficacy and safety of endoscopic resection of appendiceal orifice (AO) lesions. Primary endpoints were recurrence rate and the need for additional interventions during a clinical follow-up of at least 12 months and/or one surveillance colonoscopy. METHODS: Retrospective analysis of consecutive endoscopic resection of appendiceal lesions performed at eight centers in Spain between January 2016 and July 2023. Endoscopic resection techniques included endoscopic mucosal resection, underwater EMR (UEMR), endoscopic full-thickness resection, or endoscopic submucosal dissection. RESULTS: A total of 97 lesions were treated (median size 18 mm), 32 showing deep intra-appendicular involvement, and 62 having ≥50% circumferential involvement. UEMR was used in 52% of cases. Technical success was 93% (48% en-bloc resection). There were 6 intraprocedural and 1 postprocedural bleeding and 1 intraprocedural perforation managed endoscopically, but no cases of early post-resection appendicitis. During a median endoscopic follow-up of 23 months (n=51), 13 recurrences (25%) were identified (median time 10 months[IQR]=9-20). Piecemeal resection was significantly associated with recurrence (univariate). Deep AO extension, size ≥2cm and previous manipulation were significantly associated with piecemeal resection (multivariate). Surgery was required in 12 cases due to incomplete resection (n=7), malignancy (n=1), residual adenoma (n=2) and delayed post-resection appendicitis (n=2; at 11- and 56-months post-resection). CONCLUSIONS: Endoscopic management of AO lesions is effective and safe. However, recurrence risk emphasizes the need for long-term follow-up. Further research is required to assess delayed appendicitis risk and the optimal management of deep extension AO lesions.