A selective resection algorithm for large non-pedunculated colorectal polyps (LNPCPs) optimizes outcomes of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD)

Aims While endoscopic mucosal resection (EMR) is firmly established as the cornerstone for the management of large non-pedunculated colorectal polyps (LNPCPs≥20 mm), endoscopic submucosal dissection (ESD) has gained traction due to its potential for en-bloc and potentially curative resection in cases of intramucosal adenocarcinoma (IMC) and superficial submucosal invasive cancer (S-SMIC). However, it requires specialized training, dedicated procedural time, increased resource allocation and carries increased procedural risks. In 2017, we developed a selective resection algorithm (SRA) that aims to risk-stratify LNPCPs and facilitate informed management by EMR or ESD.

Methods Over 62 months until November 2023, all LPNCPs at a single-centre tertiary Canadian referral centre were evaluated using our SRA. Those with suspected S-SMIC (JNET 2b, Paris 0-IIc component or non-granular with pseudo-depression) or at high-risk of covert SMIC (colorectal non-granular with a Paris Is component, or rectal granular lesion with a Is component>10 mm) were selected for ESD, unless enbloc hot-EMR was considered feasible (20-25 mm size with adequate submucosal lift). Benign appearing LNPCPs underwent conventional hot-EMR and with suspected deep-SMIC were referred for surgery. Herein, we report on the patient, procedural and oncological outcomes of our SRA.

Results 362 lesions were evaluated using our SRA and subsequently underwent endoscopic resection (ESD 88, En-bloc-EMR 21, Piecemeal-EMR 253). Compared with EMR, LNPCPs undergoing ESD were more likely to be of JNET 2B classification (70.5% vs 29.5%), contain a Paris 0-IIc component (29.5% vs 6.6%) and be in the rectum (71.6% vs 5.8%, P<0.001 for all). There were no differences in technical success (EMR 96.7% vs ESD 95.5%; P=0.580). ESD took longer 146.9±76.4 vs 43.9±29.8 mins (P<0.001) and was more likely to result in a DMI requiring clip closure (31.8% vs 8.8%, P<0.001). In cases of benign pathology, where SC1 was performed, recurrence was lower with ESD (0% vs. 7.1%; P=0.05). The majority of LNPCPs undergoing EMR were benign (n=256, 93.4%), with a recurrence of 7.1% at SC1 that was readily managed endoscopically (100%). A total of 45 cancers (12.4%) were resected, with the rate greater in the ESD group (30.7% vs 6.6%). The rates of curative resection were 0/13 by piecemeal EMR, 3/5 by en-bloc-EMR and 7/24 by ESD. Of the 13 piecemeal-EMR cases, 5 may have been cured by ESD (4 right colon, 1 left colon). The remainder of non-curative cases were due to adverse tumour biology. Therefore, according to our SRA, 10/15 (66.6%) of the endoscopically curable cancers had an en-bloc R0 excision.

Conclusions Our colorectal SRA effectively identifies high-risk LNPCPs, with 30.7% of those undergoing ESD being malignant. This provides the ability to obtain a curative resection in patients with favourable tumour biology. Overall, when assessing LNPCPs amenable to cure, our colorectal SRA achieved a curative resection rate of 66.6%. Further optimisation of the algorithm may improve pre-resection identification of high-risk lesions that may benefit from en-bloc.

 

MissingLinkText

Conflicts of Interest

Authors do not have any conflict of interest to disclose.

Publication History

Article published online:
27 March 2025