Introduction

Cancer in large non pedunculated colorectal polyps (LNPCPs) may go unrecognised if it is not visible on the surface (hidden or COVERT cancer). Increasing size, non-granular morphology, rectosigmoid location and combined Paris classification have been identified as risk factors for COVERT cancer in LNPCPs.[1] It is unknown whether the size of the dominant nodule (largest Is component) in LNPCPs is correlated with risk of COVERT cancer or depth of submucosal invasion (SMI).

Aims & Methods

The endoscopic appearance and histopathology of LNPCPs ≥20 mm was analysed from a prospectively collected multicenter database of polyps referred for endoscopic resection between November 2017 and November 2023. Visible (OVERT) cancers and all serrated polyps were removed. LNPCPs with large Is components (Paris 0-Is and 0-IIa+Is polyps with Is component ≥10mm as defined by expert consensus and retrospective image review) were compared to LNPCPs without large Is component. The primary endpoint was the correlation between large Is component and presence and depth of SMI. Secondary end points were correlation between a large Is component and other risk factors for COVERT disease (location in the colon, size and morphology).

Results

3470 LNPCPs without evidence of OVERT cancer were included, of which 265 (7.6%) contained a large Is component and 3205 (92.4%) did not.
LNPCPs with large Is component were more likely to contain SMI (4.9% [95% confidence interval (CI):2.3% - 7.5%] vs. 2.1% [95% CI: 1.6% - 2.6%], P<0.01). Subgroup analysis showed that LNPCPs with a large Is component were more likely to contain superficially invasive cancer (large Is: 2.3% [95% CI: 0.5% - 4.1%] vs. no large Is: 0.7% [95% CI: 0.4% - 1.0%], P=0.01). There was no significant difference in presence of deep SMI between LNPCPs with a large nodular component vs. LNPCPs without large Is component (large Is: 2.6% [95% CI: 0.7% - 4.6%] vs. no large Is: 1.4% [95% CI: 1.0% - 1.8%], P=0.17).
LNPCPs with large Is component were larger (≥40mm; 57.0% [95% CI: 51.0% - 62.9%] vs. 37.8% [95% CI: 36.1% - 39.5%], P<0.01), more often granular (86.8% [95% CI: 82.7% - 90.9%] vs. 58.0% [95% CI: 56.3% - 59.7%], P<0.01) and found in the rectum (34.0% [95% CI: 28.3% - 39.7%] vs. 16.4% [95% CI: 15.1% - 17.7%], P<0.01) vs. LNPCPs without large Is component (Table 1).

Conclusion

LNPCPs with a Is component ≥10mm are at higher risk of containing COVERT cancer which, if present, is commonly superficially invasive. These results have implications for choice of resection technique on detection of large rectal LNPCPs with nodules ≥10mm and stratification of these patients to endoscopic en-bloc resection.

References

1. Burgess, N.G., et al., Risk Stratification for Covert Invasive Cancer Among Patients Referred for Colonic Endoscopic Mucosal Resection: A Large Multicenter Cohort. Gastroenterology, 2017. 153: p. 732-742.e1.

Introduction

International guidelines recommend endoscopic submucosal dissection (ESD) for en-bloc resection of rectal lesions suspected of submucosal invasive cancer (SMI). ESD achieves favorable outcomes for benign lesions and early rectal cancers (ERC) with superficial (<1000μm) SMI. However, for ERCs with deep (≥1000μm) SMI, the rate of histologically radical (R0) resection remains suboptimal, at maximum 64% for SM2-3 lesions, even in expert centres. The muscle-retracting sign (MRS) has emerged as a potential endoscopic marker of deep SMI detected during endoscopic resection. Predicting deep SMI is particularly relevant in rectal lesions, as incorrect selection of resection modality may lead to non-radical endoscopic resections and the need for surgical salvage, which carries significant morbidity. To address some of these limitations, we applied the novel pocket-detection method (PDM) for MRS detection. This approach enhances visualization of the submucosal space and facilitates early identification of the MRS.

Aims & Methods

The aim of this study was to evaluate the diagnostic accuracy of the MRS detected using the PDM as an innovative approach for identifying deeply invasive ERC during endoscopic resection of rectal lesions.
In this prospective, observational, single-centre study consecutive rectal lesions that underwent endoscopic resection using the PDM between August 2023 and March 2025 were included. Directionality of initial submucosal dissection targeted any morphological or surface vascular pattern at risk of deep SMI to attempt MRS identification. Histopathology was the reference standard for MRS diagnostic accuracy in detecting deep SMI. Deep SMI was defined as ≥1000μm invasion from the muscularis mucosa at histopathology.

Results

38 rectal lesions, median size 30 mm (IQR 20-40), were included. PDM for MRS detection was successful in all cases, with MRS-positive in 15/38 (39.5%). Deep SMI was confirmed in 15/38 (39.5%). Accuracy of MRS-positive for deep SMI detection was 84.2%, (95% CI 69.6-92.6%), sensitivity 80% (95% CI 54.8-92.9%), specificity 87% (95% CI 67.9-95.5%), positive predictive value 80% (95% CI 54.8-92.9%), negative predictive value 87% (95% CI 67.9-95.5%), positive likelihood ratio 6.13, negative likelihood ratio 0.23, area under the curve 0.83 (95% CI: 0.71–0.96). The rate of R0 resection was 92.1% (35/38).

Conclusion

MRS detected using the PDM demonstrated moderate-to-high accuracy in predicting deep SMI in early rectal cancer. This finding may allow selection of endoscopic resection strategy based on invasion depth.

Introduction

Endoscopic submucosal dissection (ESD) is increasingly promoted as the optimal treatment strategy for all large non-pedunculated colorectal polyps (LNPCP). The effect of a universal en bloc strategy on oncological outcomes for the treatment of LNPCP in the right colon is unknown. We evaluated this in a large Western population.

Aims & Methods

We retrospectively analysed prospectively collected data from major tertiary centres where patients were referred for endoscopic resection (ER) of LNPCP (N=5084). Patients found to have cancer after ER and those referred directly to surgery were included. The primary outcome was to determine the proportion of right colon LNPCP with low-risk cancer.

Results

Over 180 months until June 2023, 3294 sporadic right colon LNPCP in 2956 patients were referred for ER at 7 sites (median size 30mm [IQR 15]). 63 (2.1%) patients were referred directly to surgery and cancer was proven in 56 (88.9%). 2851/2956 (96.4%) LNPCP underwent ER (median size 35mm [IQR 20]) of which 75 (2.6%) were cancers. The overall prevalence of cancer in the right colon was 4.4% (131/2956). Detailed histopathological analysis was possible in 115/131 (88%) cancers (71 after ER, 44 direct to surgery, Table 1). 23/2940 (0.78%) sporadic right colon LNPCP were low-risk cancers.

Table 1: Final Oncologic Outcomes; comparison between histopathologic variables of cases referred directly to surgery versus following endoscopic resection

Conclusion

The proportion of right colon LNPCP referred for ER containing low-risk cancer amenable to endoscopic cure was <1%, in a large, multicentre Western cohort. A universal ESD strategy for the management of right colon LNPCP is unlikely to yield improved patient outcomes given the minimal impact on oncological outcomes, significant resource demands and increased adverse events.

Introduction

Cancer in large non-pedunculated colorectal polyps (LNPCPs) is poorly discriminated outside expert centres. It is unknown whether video- is comparable to live-assessment for determining submucosal invasion (SMI) in LNPCPs. Video-assessment has multiple advantages including collaborative discussion of imaging findings at multi-disciplinary meetings avoiding extra assessment procedures for patients and incorrect decision-making. We compared live LNPCP assessment with analysis of high-quality endoscopic videos produced by an expert.

Aims & Methods

Blinded live assessments of LNPCPs from consecutive, consenting patients were conducted by 15 endoscopists in a single center. After the live assessment, an expert recorded a standardized video of each LNPCP. The remaining endoscopists [who had not assessed the LNPCP live] assessed these videos using an online survey. Endoscopists were classified as experienced (>50 EMRs ever and >1000 colonoscopies) or inexperienced. Parameters such as Blink Impression(BI) [1], 6-Blink Features(BF) – namely fold deformation, extra redness, depression, chicken skin mucosa, ulceration and spontaneous bleeding - presence of a Demarcated Area(DA), Vascular Pattern(VP) of any DA, size, location, Paris classification, and morphology were recorded to form the endoscopist's impression of cancer presence in the LNPCP. The results were later compared to expert consensus including an external validator. The primary endpoint was to evaluate the accuracy of endoscopists’ final impression of cancer and choice of correct treatment between live and video assessments.

Results

64 live assessments (12 endoscopists) & 96 video assessments (9 endoscopists) of 18 LNPCPs were performed. 5 (41.7%) (live) vs 4 (44.4%) (video) endoscopists were inexperienced. The comparison of live versus video assessments revealed no significant difference in the final impression of cancer presence by the endoscopist (sens 80.0% vs 100%, spec 87.0% vs 85.5%), BI (sens 85.7% vs 92.3%, spec 88.6% vs 80.7%) and the presence of ≥2BF (sens 71.4% vs 84.6%, spec 81.8% vs 68.7%) vs histology (P=.77, .34 & .21 respectively). Further the ability of DA & JNET to predict SMI did not differ nor did the rate of correct treatment determination (71.9% live vs 60.4% video, P=.14). Versus expert consensus the determination of ≥2BF was equally accurate live (82.4%) vs video (76.0%,P=.38). Conversely the exact number of BF vs experts (live 60.4% vs video 37.5%,P=.01), the presence of ≥3 features (location, size, morphology or Paris classification) of COVERT (not visible on the surface) SMI live (81.3%) vs video (65.6%, P=.03) and the correct outcome of a structured algorithm[2] (live 96.9%, video 81.3%,P=.002) were determined differently between the groups.

Conclusion

Final impression of the presence of cancer and determination of correct treatment in LNPCPs are predicted equally well from blinded video assessment versus live assessment in a group of similarly experienced endoscopists. This finding could minimise the need for patients to undergo a repeat procedure to assess their LNPCP prior to resection relying instead upon expert assessment of a video.

References

• Debels, L., Smeets, S., Poortmans, P. J., Jorissen, C., Lala, V., Lamiroy, T., Valori, R., Desomer, L., Anderson, J., & Tate, D. (2023). Identification of 6 key features of colorectal polyps increases the sensitivity of cancer detection and ability to discriminate deep submucosal invasion - The basis of the BLINK (first) impression? Gastrointestinal Endoscopy, 97(6, Supplement), AB190. https://doi.org/10.1016/j.gie.2023.04.318
  
• GIEQS. Year. "SMIC." Accessed [23/11/2023]. https://www.gieqs.com/smic.

Introduction

Post-polypectomy guidelines classify individuals with polyps ≥10mm, in the absence of other high-risk features, as being at increased risk for developing colorectal cancer (CRC). Consequently, these individuals are recommended to undergo strict surveillance at three-year intervals. However, the necessity of such strict surveillance, particularly for polyps measuring between 10-20mm, remains a subject of ongoing debate. To shed light on this debate, this study aims to compare the risk of post-colonoscopy colorectal cancer (PCCRC) between individuals with polyps ≥10mm, in the absence of other high-risk features, and individuals without polyps.

Aims & Methods

For this study, data of quality-assured baseline colonoscopies performed between 2014 and 2020 as part of the Dutch fecal immunochemical test-based CRC screening program were used. In accordance with the guidelines in place at that time, a subset of individuals with adenomas ≥10mm without high-grade dysplasia and serrated polyps ≥10mm without dysplasia were advised a 5-year surveillance interval, rather than the currently recommended 3-year interval. For these individuals, the PCCRC-risk within 5 years was assessed and compared to that of individuals without polyps at baseline colonoscopy using multilevel cox regression analysis. Additionally, the adenoma detection rate (ADR) of endoscopists was categorized into tertiles to evaluate the impact of endoscopist quality on PCCRC-risk in individuals with polyps ≥10mm without other high-risk features.

Results

Among all included individuals in the Dutch screening program with high-risk polyps (n=74.289), 79% had polyps ≥10mm and 46% had polyps measuring 10-20mm as the sole high-risk feature. In total, 21.522 individuals with ≥10mm polyps without other high-risk features who were advised a 5-year surveillance, and 68.688 individuals without polyps who were referred back to the screening program after 10 years, were included in PCCRC-risk analysis. Within 5 years, there were 21 and 108 cases of PCCRC observed in these groups, respectively. Individuals with ≥10mm polyps at baseline colonoscopy had a comparable risk of PCCRC within 5 years to those without polyps (HR 0.67; CI95% 0.42-1.07). The PCCRC-incidence was 3.07 (CI95% 1.76-4.38) per 10.000 person-years of follow-up (PYFU) in individuals with ≥10mm polyps, and 5.02 (CI 95% 4.08-5.97) per 10.000 PYFU in individuals without polyps. PCCRC incidence in individuals with polyps ≥10mm without other high-risk features was lowest when colonoscopy was performed by endoscopists with high ADR, at 0.93 per 10.000 PYFU (CI95% 0.66-2.23), compared to 5.78 (CI95% 2.64-8.93) per 10.000 PYFU in those scoped by endoscopists with low ADR (HR 5.85 CI95% 1.28-26.55).

Conclusion

PCCRC-risk within 5 years among individuals with polyps ≥10mm as the sole high-risk feature is low and comparable to that of individuals without polyps at baseline colonoscopy. Notably, the risk for individuals with ≥10mm polyps significantly reduced when colonoscopies were performed by endoscopists with high ADR. Lengthening the surveillance interval from 3 to 5 years for individuals with polyps ≥10mm as their sole high-risk feature would concern 79% of all individuals with high-risk polyps, or 46% when limited to those with 10-20mm polyps. This could ease the burden on colonoscopy capacity and allow for more cost-effective use of resources.

Disclosure

ED: Honoraria for consultancy from Olympus, Fujifilm, Ambu, InterVenn, Norgine and Exact Sciences. Speakers' fees from Olympus, Norgine, IPSEN/Mayoly, FujiFilm, Steris and Pentax. Endoscopic equipment on loan of FujiFilm.
MS: received research support from Sysmex, Sentinel, Norgine and Medtronic
All other authors (NR and JIJ, ML) have nothing to disclose.