CLIP PLACEMENT DOES NOT PREVENT DELAYED BLEEDING AFTER ENDOSCOPIC MUCOSAL RESECTION (CLIPPER) FOR LARGE POLYPS IN THE PROXIMAL COLON: A MULTICENTER, RANDOMIZED CONTROLLED TRIAL

Background: The most common complication after endoscopic mucosal resection (EMR) is delayed bleeding (DB), especially in the proximal colon. Randomized controlled trials in high volume centers suggest that prophylactic clipping (PC) of the resection defect reduces DB in patients with a high DB risk. Guidelines already recommend PC for proximal polyps, despite being technical difficult and expensive. We aimed to evaluate the value of PC in patients receiving EMR for proximal flat polyps in reducing DB in daily clinical practice.
Methods: We performed a randomized controlled trial in 19 Dutch hospitals with patients referred for EMR of lateral spreading and sessile polyps ≥ 20mm in the proximal colon. Patients were randomly assigned (1:1) to groups treated with PC (intervention group) or no PC (control group). PC was standardized in tutorial meetings focusing on approximating the resection margins with aligning clips 5-10mm apart. The primary endpoint was clinically significant DB defined as hematochezia necessitating emergency department presentation, hospitalization, or re-intervention within 30 days post-EMR, which was analyzed according to the intention-to-treat principle. The trial is registered at ClinicalTrials.gov, NCT03309683.
Results: Between May 15, 2018 and December 14, 2021, 356 patients with a median polyp size of 30mm (IQR 25,40) were included of whom 179 were randomly assigned to the control group and 177 to the intervention group. DB occurred in 11 (6.1%) patients of the control group and in 16 (9.0%) patients of the intervention group (p=0.30). Endoscopists reported complete defect closure in 70.6% of cases. There were no differences between the control and intervention group in serious adverse events including perforation (two versus one, p=0.57), post polypectomy syndrome (zero versus three, p=0.08) and intensive care unit admission (one versus one). No deaths were reported.
Conclusion: PC did not reduce DB in patients undergoing EMR for large lateral spreading and sessile polyps in the proximal colon. Therefore, this study demonstrates that the burden of laborious and expensive PC is not justified in daily clinical practice.
Funding: The CLIPPER trial is investigator initiated and is financially supported by the Dutch Digestive Foundation (MLDS). Olympus (Japan) contributed Quick Clip Pro endoclips for this trial.