Technical Failure During Colorectal Endoscopic Full Thickness Resection: the “through Thick and Thin” Study.

Background: Endoscopic full-thickness resection (EFTR) is an effective and safe technique for non-lifting colorectal lesions. Technical issues or failures with full-thickness resection device (FTRD) system are reported but there are no data about their details. The aim of our study was to quantify and classify FTRD technical failures. Patients and methods: We performed a retrospective study involving 17 Italian centres with experience in advanced resection techniques and OVESCO devices. Each centre shared and classified all the consecutive failures prospectively collected during colorectal EFTR by using FTRD from 2018 to 2022. Primary outcome was technical failure rate and classification; secondary outcomes included management, clinical success, and complications’ assessment in this population. Results: Included lesions were mainly recurrent (52%), with mean dimension of 18.4 (± 7.5) mm. Among 750 EFTRs, failures occurred in 77 patients (35 F, mean age 68.9 ±8.9 years). A classification was proposed in type I snare uncutting (53.2%), type II clip misdeployment (31.2%) and type III cap misplacement (15.6%). Among endoscopic treatment completed, rescue EMR was performed in 57 patients (79%), allowing en-bloc and R0 resection in 71% and 64% cases, respectively. Overall adverse events rate was 27.3%. Pooled estimates for the rate of failure, complications and rescue endoscopic therapy were similar between low- and high-volume centres (p=0.08, p = 0.702 and p= 0.713). Conclusions: Colorectal EFTR with FTRD is a challenging technique with a not negligible rate of technical failure and complications. Experience in rescue resection techniques and multidisciplinary management are mandatory in this setting.