Introduction

Endoscopic resection (ER) of large non-pedunculated colorectal polyps (LNPCP) has advanced significantly, pushing boundaries to treat lesions of any size. However, a dearth of published data exists on the extremes of ER practice, particularly for large lesions creating circumferential or near-circumferential mucosal defects. While Japanese studies, focusing on ESD-resected LNPCP, show conflicting outcomes, two prominent Western series lean towards EMR-resected lesions. The Western landscape is evolving, with a notable rise in ESD for LNPCP. Our study delivers fresh insights, presenting outcomes from ER with ≥75% circumferential mucosal defects in a leading Western centre that predominantly favours ESD for such lesions. This signifies a transformative trend in ER methodology, underlining the efficacy of ESD in addressing intricate colorectal lesions, thereby shaping evolving standards.

Aims & Methods

1477 ERs of LNPCP ≥20mm were performed and grouped according to the extent of the mucosal defect and comparisons made between those with <75% and ≥75% defects. Independent predictors of stenosis were identified.

Results

137 patients had ER leaving ≥75% circumference defect, most located at or distal to the rectosigmoid, with ≥90% defects in 29 and 100% in 14. 31 (22.6%) were resected using EMR and 106 (77.3%) using ESD. En bloc resection was achieved in 64%, increasing to 88% in the last 4 years of the study where ESD was increasingly employed routinely. Overall complications were more likely in these patients (11.7% versus 3.4%, p<0.001), although there was no difference in the incidence of clinically significant perforation (p=0.41) or post-procedure bleeding (p=0.45). 101 patients had undergone surveillance. Stenosis developed in only 2 of 71 (2.8%) patients with defects ≥75% circumference but 10 of 18 (55.6%) patients with defects ≥90% and 10 of 12 patients (83.3%) with 100% circumferential defects. ≥90% circumference defect was an independent risk factor for stenosis (p<0.001). All patients with stenosis were managed successfully with either expectant management if asymptomatic or balloon dilatation. None have required surgical intervention for stenosis. Recurrence was more likely in those with ≥75% defect (OR 7.9, 95% CI 3.8-16.4, p<0.001) but was acceptable at an incidence of 15% at SC1

Conclusion

This is the largest western series to date reporting on outcomes of ER of LNPCP leaving near or fully circumferential defects, and the first to include significant numbers of ER performed by ESD. ER of LNPCP resulting in defects ≥75% of the luminal circumference is challenging but highly effective in avoiding surgery when performed in an expert centre. En bloc resection can be achieved in most cases, reducing recurrence. The only independent predictor of stenosis is ≥90% circumference defect but some patients improve with expectant management therefore pre-emptive intervention may not be warranted.

Introduction

The safety and efficacy of endoscopic resection (ER) as a first-line treatment for large non-pedunculated colorectal polyps (LNPCP) is well established. Significant complications are infrequent. Risk factors for immediate perforation have been described although it is frequently amenable to endoscopic closure and rarely results in significant deleterious sequelae. Delayed perforation or sepsis is a rare complication with potentially devastating consequences. Emergent surgery may be necessary with its attendant major complications. Risk factors for delayed perforation/sepsis after ER of LNPCP are not well established.

Aims & Methods

We analysed a large series of advanced ER of LNPCP to identify factors associated with delayed perforation.
Consecutive patients with LNPCP treated by ER at a tertiary referral centre between September 2011 and September 2023 were included. Lesions were resected using EMR, piecemeal EMR and ESD. Univariate analysis was used to examine clinicopathological factors potentially associated with delayed perforation.

Results

1883 ER for LNPCP were performed over the study period with a mean size of 46.4mm +/- 26.4mm (median 40mm, range 20-210mm). ESD was used for 890. Delayed perforation or sepsis occurred in 24 (1.3%) patients of which 8 (0.4%) required emergent surgery and 1 required CT guided drainage of an abscess. 3 patients developed sepsis after ESD of rectal lesions without evidence of perforation on CT with luminal contrast and required intensive care unit (ICU) management. There was no mortality. In patients who suffered a delayed perforation or sepsis, 54% of LNPCP were in the right colon, 8% in the left colon and 38% in the rectum. Delayed perforation/sepsis was significantly associated with extreme size (OR 3.02, 95% CI 1.35-6.76, p<0.001); difficult access (OR 2.63, 95% CI 1.16-5.97, p=0.02); ESD (OR 4.08, 95% CI 1.52-10.98, p=0.003) and long procedure time over 240 min (OR 5.20, 95% CI 2.02-13.36, p<0.001) but not location, F2 fibrosis, or age.

Conclusion

Delayed perforation/sepsis after ER of LNPCP is rare, and a requirement for surgery extremely rare, but varies according to lesion and procedure characteristics. The consequences can be severe and include surgery, guided drainage or ICU admission. Delayed perforation/sepsis can affect patients with LNPCP in any location including the rectum. Given the risk factors identified in this study, these data could help realistically counsel patients with LNPCP of extreme size, difficult access and requiring complex prolonged procedures regarding the risks of delayed perforation and sepsis.

Introduction

Studies report that almost 50% of Large Non-Pedunculated Colorectal Polyps (LNPCP) have been subjected to heavy manipulation in form of prior attempts at resection or extensive biopsy sampling prior to referral to an expert centre. This significantly impacts several critical outcomes of endoscopic resection (ER). However, understanding of standardised classifications of LNPCP, endoscopic diagnosis and indications for ER has increased in general endoscopy practice which may have improved decision making prior to referral. We aimed to compare trends in patterns of prior injudicious manipulation and the significance of biopsy sampling over sequential time periods in a large cohort of patients referred to a tertiary referral centre for ER.

Aims & Methods

Referral documentation, including clinic and referral letters, endoscopy reports, and histopathology result, were reviewed for evidence of prior resection attempts or biopsy sampling. Data included the number of biopsy samples taken and corresponding histological results. Patients referred between January 2011 and August 2024 were categorised into five time periods. Heavy manipulation was defined as either a prior resection attempt or ≥6 biopsy samples. Analyses included comparisons of resection attempts, heavy manipulation, biopsy sampling, and the detection of high-grade dysplasia on biopsies (as a marker of improved lesion assessment and targeted sampling). Trends in practice changes were assessed using the Chi-square test for trend.

Results

1407 LNPCP were treated by ER. There was a significant trend toward fewer prior failed attempts at resection over sequential time periods with 30% in Period 1 and only 11% in Period 5 (p<0.001); fewer LNPCP subjected to heavy manipulation with 61% in Period 1 and 27% in Period 5 (p<0.001) and fewer LNPCP with prior biopsy sampling with 77% in Period 1 and 47% in Period 5 (p<0.001). However, there was no trend found for an improvement in biopsy sampling yields of HGD with 18% in Period 1 and 25% in Period 5 (p=0.1).

Conclusion

In a large cohort of ER of LNPCP, this study demonstrates a significant reduction over time in failed resection attempts, heavy manipulation, and biopsy sampling of LNPCP before referral to a tertiary centre for endoscopic resection (ER). This suggests an improvement in endoscopic lesion assessment and decision making by general endoscopists. However, heavy manipulation remains a significant problem. Although fewer LNPCP are biopsied prior to referral, the yield of significant findings did not change, suggesting biopsies are not effectively targeted, and highlighting the need for further improvements in lesion assessment.

Introduction

Resection of large non-pedunculated colorectal polyps (LNPCP) located in the rectum varies by institution and region with some, particularly colorectal surgeons, favouring TEM and others endoscopic resection (ER). There is a paucity of data directly comparing these strategies and the procedure of choice remains under debate. Our unit is a tertiary referral centre for complex polyps and early colorectal cancer. All rectal LNPCP were treated by TEM until a change in practice from 2011 when the first-line therapeutic strategy for rectal LNPCP changed to ER.

Aims & Methods

We aimed to report the outcomes of TEM and ER of rectal LNPCP from a large tertiary cohort. Large (≥20mm) rectal adenomas resected by TEM or ER (2009 – 2023) were analysed. From 2009-2011 all rectal adenomas were treated by TEM, after which the primary resection strategy changed to ER. Outcomes were compared between techniques. Given the difference in resection strategy, a composite outcome of septic complications included clinically significant perforation for ER (early or delayed perforation requiring any form of unplanned medical or surgical treatment) and septic complications for TEM (peritonitis or pelvic/anorectal sepsis).

Results

704 rectal adenomas were resected by TEM (n=71), EMR (n=145) and ESD/Hybrid ESD (n=488) with a mean size of 45mm for TEM vs 55mm for ER (p<0.001). 100% of patients undergoing TEM required hospital admission vs 15% for ER (p<0.001), and 100% required general anaesthesia (GA) for TEM vs 26%% for ER (GA or propofol sedation, p<0.001). En bloc resection was achieved for 96% of ESD resections, 54% of TEMS, 28% of EMR and 14% of hybrid ESD (p<0.001). The incidence of complications were similar (9.9% for TEM versus 5.0% for ER, p=0.10). Recurrence occurred in 2.7% after ESD, 21.1% after EMR, 23.6% after Hybrid ESD and 36.4% after TEM (p<0.001). No patients undergoing ER or TEM required surgery as a result of a complication.

Conclusion

Despite significantly larger lesion sizes, ER in our institution provides far superior results for patients than TEM with relatively fewer patients requiring hospital admission and lower recurrence rates, especially with ESD. En bloc resection was more likely with ER as a result of the difficulty achieving en bloc resection for extremely large lesions with TEM, which can invariably be resected en bloc by ESD. These results have led to a policy of ER for all apparently benign rectal tumours regardless of size and, in recent years, ESD as the primary approach for all rectal lesions.

Introduction

Endoscopic resection (ER) techniques for treating large non-pedunculated colorectal polyps (LNPCP) have advanced significantly and the relevance of early studies reporting outcomes may diminish with time. EMR remains the predominant therapeutic option for LNPCP in western practice, but ESD is increasingly employed. Limited studies demonstrate safety and efficacy for highly selected patients, but no studies examine the practical introduction of ESD (which has a steep learning curve) as a standard component of ER strategies in real-world practice.

Aims & Methods

Patients with LNPCP treated by ER at a tertiary referral centre between January 2011 and September 2023 were included. ERs were divided into 2 time periods (Period 1: January 2011 – May 2018 and Period 2: June 2018 – September 2023). Resection technique and outcomes including en bloc resection, successful single-session resection and complications were compared for procedures between Period 1 and Period 2.

Results

1563 LNPCP were treated with ER over the study period. ER was successful in 1517 (97%). The mean lesion size was 46.9mm +/- 26.3mm (median 40mm, range 20mm–210mm). 774 LNPCP were resected using EMR/pEMR and 743 by ESD/Hybrid ESD. ESD was used to resect 476 (64%) LNPCP during Period 2 compared to 267 (34.7%) during Period 1 (p<0.001). Whilst introducing ESD into practice during Period 1, a combination of Hybrid ESD and ESD were used with an en bloc resection rate of 64%, but en bloc resection for ESD increased to 98% during Period 2 (p<0.001). 97% of rectal LNPCP were resected by ESD during period 2 compared to 62% during period 1 (p<0.001). 45% of colonic LNPCP were resected by ESD during period 2 compared to 17% during period 1 (p<0.001). Complications occurred less frequently in Period 2 compared to Period 1 (2.9% versus 5.1%, p=0.04) and there was no difference in the rate of clinically significant perforation (1.2% versus 1.0%, p=0.76) or post-procedure bleeding (1.5% versus 1.6%, p=0.89). Fewer patients were admitted to hospital during period 2 compared to period 1 (5.6% versus 14.8%). Training occurred more frequently in Period 2 with 258 (35%) ERs performed in part or completely by an endoscopy fellow compared to 126 (16%) in period 1. 105 (22%) ESDs were performed in part or completely by an endoscopy fellow during Period 2 compared to 30 (11%) during period 1.

Conclusion

These data demonstrate the evolving nature of endoscopic resection practice in modern advanced practice. Large volume ESD can safely be incorporated into standard practice with a near-exclusive policy of ESD to treat all rectal LNPCP and nearly half of colonic LNPCP resected by ESD. En bloc resection rates comparable to Japanese expert centres can be achieved with no effect on complications. Moreover, regular training in ESD can safely be introduce.

Disclosure

Nothing to disclose

Introduction

Endoscopic resection (ER) is the preferred treatment for large non-pedunculated colorectal polyps (LNPCP) in many centres.

Despite standardized classification systems, discrepancies exist between the endoscopic assessment by experts in tertiary ER referral centres and endoscopists in peripheral settings. This significantly impacts planning for ER, leading to duplicated procedures and increased burdens on patients and healthcare.

Aims & Methods

Our aim was to compare the final morphology, surface characteristics, histological diagnosis, and lesion size of LNPCPs referred to a tertiary center for consideration of ER with the exact descriptions provided during the initial referral.
We included patients with LNPCP referred for ER at a tertiary referral centre between June 2022 and September 2023.
Clinical referrals were assessed for morphological classification (Paris/Japanese classifications), surface characteristics (pit pattern and/or vascular pattern), estimated lesion size, and preliminary endoscopic diagnosis.
We compared the endoscopic diagnosis and size with our unit’s advanced endoscopic assessment. The final confirmed size of the lesion after ER was also recorded for comparison.

Results

A total of 328 LNPCP were assessed and resected following referral during the study period. The location of LNPCP was the most consistently reported feature by referring endoscopists (98.2%).
Standardised morphology according to Paris/Japanese classifications was reported in only 133 cases (40.7%). Pit pattern evaluation was reported in 109 cases (33,2%), while vascular pattern evaluation was reported in 66 cases (20,1%).
A size estimate was provided in 276 cases (84.2%). However, 51 cases (18.6%) underestimated the size by ≥20mm compared to the final LNPCP size after ER.
Regarding suspected diagnoses of invasive cancer, 50 cases (15.3%) were suspected, of which 15 had a final diagnosis of invasive cancer. In 277 cases (84.7%) with no suspicion of invasive cancer, 15 had a final diagnosis of invasive cancer, resulting in a sensitivity of 50% and specificity of 88% for a final diagnosis of invasive cancer.
After advanced endoscopic assessment, a diagnosis of likely invasive cancer was made for 41 LNPCP, resulting in a sensitivity of 73% and specificity of 93% for a final diagnosis of invasive cancer. This sensitivity is however most likely an underestimation, due to the number of lesions that were previously manipulated (biopsies, attempted resection), complicating surface characterization.

Conclusion

Despite broad agreement on standardised reporting and classifications for endoscopic diagnosis, our study reveals significant deficiencies in the assessment of LNPCP outside of specialist centres. The majority of referred LNPCP lacked a morphological classification and detailed interrogation of surface characteristics.
These shortcomings, coupled with the limited sensitivity for diagnosing potential invasive cancer, hinder the ability to plan advanced resection without subjecting patients to a further procedure for lesion assessment, with its attendant patient and institutional burdens.
Moving forward, efforts should be made to improve the quality and consistency of LNPCP assessment in non-specialist settings. This may involve enhanced training and education for endoscopists, as well as the development of standardized protocols for LNPCP evaluation and referral. Further research is warranted to explore optimal strategies for improving diagnostic accuracy and streamlining patient management in this context.