Endoscopic mucosal resection (EMR) is an effective and has been widely used technique for the treatment of superficial colorectal neoplasms. Although, conventional EMR (CEMR) showed high efficacy for the management of colorectal superficial neoplasms, there is problematic limitation in this technique - incomplete resection. In literature, the anchoring-tip EMR (AEMR), named as "Tip-in EMR" was first introduced in 2016 from Japan. Recently, several retrospective studies have been suggested about the effectiveness of AEMR. However, there has been no prospective randomized controlled study to identify its advantage over CEMR. Therefore, the investigators performed a multicenter randomized controlled trial to estimate the effectiveness of AEMR compared with CEMR for the endoscopic treatment of intermediate-size (10 to 20 mm) colorectal polyps.

After injection of normal saline solution mix, snaring was tried for CEMR. In AEMR, the snare tip was projected from the sheath by 1-2 mm length. Consequently, a small mucosal incision was made at proximal side of lesion. Then the snare was deployed progressively and adjusted around the lesion trying to obtain free margins. At the final step of both conventional and Tip-in EMR, the lesion was resected.

Inclusion Criteria:

• Intermediate-size (10 to 20 mm) colorectal polyps
• Morphologically sessile (Is), slightly elevated (IIa), flat (IIb), and slightly depressed (IIc) as Paris classification of superficial neoplastic lesions
• Laterally spreading tumor (granular and nongranular type) as Kudo classification.

Exclusion Criteria:

• Pedunculated or excavated/ulcerated polyps
• Polyps with features strongly suggestive of submucosal invasive carcinoma
• Polyps in patients with inflammatory bowel disease, familial polyposis, electrolyte abnormality, and coagulopathy
• Residual lesions after endoscopic resection or presence of severe submucosal fibrosis.