Randomized Trial Finds Tip-In (Anchoring) EMR Superior to Conventional EMR for 10- to 25-mm Nonpedunculated Colorectal Polyps

“Tip-in” or “anchoring” endoscopic mucosal resection (A-EMR) involves submucosal injection followed by a small incision on the proximal side of the injection mound. The snare tip is then anchored into this incision, and the snare is opened over the lesion. The anchoring process keeps the snare tip in place with a margin on the proximal side, and pushing the snare as it opens over the lesion widens the snare diameter, helping to ensure clean lateral margins. One study found that A-EMR was associated with perforation when used for lesions ≥20 mm; in general, though, any time snaring is used to excise large areas, the risk of perforation increases except, perhaps, with underwater EMR. 

In a randomized controlled trial from Korea, 211 nonpedunculated colorectal lesions 10- to 25-mm in size (median size, 14 mm) in 164 patients were randomized to A-EMR or conventional EMR (C-EMR). The complete resection rate (en bloc resection with no visible residual polyp or equivocal residual polyp that was negative on biopsy) was 89.5% with A-EMR versus 74.5% with C-EMR (P=.011). In addition, R0 resection was 77.1% with A-EMR versus 64.2% with C-EMR (P=.074). In subgroup analyses, A-EMR provided better complete resection rates for lesions >15 mm, right-sided colon lesions, and both flat and protruded lesions.