Endoscopic Management of Large Non-Pedunculated Colorectal Polyps

Abstract

Large non-pedunculated colorectal polyps ≥20 mm (LNPCPs) comprise approximately 1% of all colorectal polyps. LNPCPs more commonly contain high-grade dysplasia, covert and overt cancer. These lesions can be resected using several means, including conventional endoscopic mucosal resection (EMR), cold-snare EMR (C-EMR) and endoscopic submucosal dissection (ESD). This review aimed to provide a comprehensive, critical and objective analysis of ER techniques. Evidence-based, selective resection algorithms should be used when choosing the most appropriate technique to ensure the safe and effective removal of LNPCPs. Due to its enhanced safety and comparable efficacy, there has been a paradigm shift towards cold-snare polypectomy (CSP) for the removal of small polyps (<10 mm). This technique is now being applied to the management of LNPCPs; however, further research is required to define the optimal LNPCP subtypes to target and the viable upper size limit. Adjuvant techniques, such as thermal ablation of the resection margin, significantly reduce recurrence risk. Bleeding risk can be mitigated using through-the-scope clips to close defects in the right colon. Endoscopic surveillance is important to detect recurrence and synchronous lesions. Recurrence can be readily managed using an endoscopic approach.

Keywords: colonoscopy; colorectal cancer; endoscopic mucosal resection; endoscopic submucosal dissection; polyp; polypectomy.

Figure 1

Endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD) and cold-snare EMR (C-EMR). (a–c) EMR of a 40 mm Paris 0-IIa+Is granular hepatic flexure lesion. (d–f) ESD of a hemi-circumferential 45 mm Paris 0-IIa+Is granular rectal lesion. (g–i) C-EMR of a 50 mm serrated lesion without dysplasia in a patient with serrated polyposis syndrome.

Figure 2

A 35 mm granular Paris 0-IIa LNPCP in the mid-ascending colon, assessed using (a) high definition white light, (b) narrow band imaging (NBI) and (c,d) near-focus with NBI, demonstrating a homogenous pit pattern (Kudo pit pattern IV).

Figure 3

A 20 mm sessile serrated Paris 0-IIa LNPCP in the proximal ascending colon, assessed using (a,b) near focus and (c,d) near focus with narrow band imaging (NBI). There is a central well-demarcated area with loss of homogeneity, neovascularization, dilated vessels and a non-structural pit pattern (Kudo pit pattern V_N), suggestive of a deeply invasive cancer.