Introduction

Self-expanding metal stents (SEMS) are recommended by guidelines to relieve biliary obstruction caused by malignant strictures in a palliative setting. There are three types of SEMS, uncovered (UC), semi-covered (SC), and fully covered (FC) indicating the degree to which they are covered by a plastic film. The main concerns regarding bile duct stents are their ability to provide adequate drainage, maintain long-term patency, and overall safety. The intention with the plastic covering is to prevent tumour ingrowth and occlusion of the stent. However, this also makes the stents more liable to dislodge spontaneously (1). There are conflicting reports on UC and SC stents regarding long-term patency; some studies have shown a higher frequency of dysfunction in UC stents while others have not (2, 3). Only a few studies have examined the use of FC stents(4). The aim of this study is to examine the differences in long-term patency of UC, SC, and FC SEMS in palliative patients with jaundice caused by malignant obstruction of the distal bile duct.

Aims & Methods

In this prospective randomized multicenter study patients were recruited between March 2020 and August 2024 at 13 centers in Sweden performing ERCPs. Patients with malignant extrahepatic strictures, where curative surgery was considered unlikely, were included. Patients were randomized in a 1:1:1 ratio to receive UC, SC, or FC SEMS and followed sequentially for 12 months. The primary outcome was stent failure defined as either the patient undergoing re-ERCP or other biliary drainage intervention or clinical and laboratory signs indicating stent dysfunction. Patients were censored at stent failure, death, time point of curative surgery or when the follow-up time ended. This study was registered at ClinicalTrials.gov (NCT06453590).

Results

A total of 450 patients who had reached their respective endpoints were included in this preliminary intention-to-treat analysis: 163 patients in the UC group, 151 in the FC group and 136 in the SC group. The majority (83%) of the patients had pancreatic cancer. After 12 months of follow-up, 50 patients (11%) were alive with a functioning stent, 151 patients (34%) had received palliative oncological treatment, and 18 patients (4%) had undergone surgery with curative intent. Stent failure occurred in 17% (95% CI: 11-23%) of the UC group, 13% (95% CI: 7-18%) of the FC group, and 7% (95% CI: 3-12%) of the SC group. The failure rate was lower in the SC group (HR 0.4; 95% CI: 0.2-0.8) compared to the UC group. There was a non-significant difference in failure rate in the FC group (HR 0.7; 95% CI: 0.4-1.3) relative to the UC group.

Conclusion

To our knowledge, this is the first prospective randomized trial comparing the long-term patency of the three different types of SEMS. The results suggest that semi-covered SEMS have the lowest rate of stent failure in patients with extrahepatic malignant obstruction and may therefore be the most appropriate choice of stent for palliative patients.

References

1. Kim HS, Lee DK, Kim HG, Park JJ, Park SH, Kim JH, et al. Features of malignant biliary obstruction affecting the patency of metallic stents: a multicenter study. Gastrointest Endosc. 2002;55(3):359-65.
2. Saleem A, Leggett CL, Murad MH, Baron TH. Meta-analysis of randomized trials comparing the patency of covered and uncovered self-expandable metal stents for palliation of distal malignant bile duct obstruction. Gastrointest Endosc. 2011;74(2):321-7.e1-3.
3. Almadi MA, Barkun AN, Martel M. No benefit of covered vs uncovered self-expandable metal stents in patients with malignant distal biliary obstruction: a meta-analysis. Clin Gastroenterol Hepatol. 2013;11(1):27-37.e1.
4. Yamashita Y, Tachikawa A, Shimokawa T, Yamazaki H, Itonaga M, Sakai Y, et al. Covered versus uncovered metal stent for endoscopic drainage of a malignant distal biliary obstruction: Meta-analysis. Dig Endosc. 2022;34(5):938-51.

Disclosure

The study received partial funding from Boston Scientific Nordic AB

Introduction

Computer-aided diagnosis (CAD) systems are widely implemented in the medical field for the analysis of medical images. PolyDeep is a CAD system that has demonstrated its efficacy in lesion detection.

Aims & Methods

The aim of this study is to determine whether PolyDeep increases the adenoma detection rate (ADR) in the context of expert endoscopists participating in a regional, population-based colorectal cancer screening program in Spain. PolyDeep Advance 3 (NCT05513261) is a multicentric, randomized controlled clinical trial. For the primary endpoint, we aimed to assess whether the ADR is superior in PolyDeep-assisted colonoscopy compared to conventional colonoscopy. As secondary endpoints, we aimed to determine whether PolyDeep-assisted colonoscopy improves the polyp detection rate (PDR), serrated lesion detection rate (SLDR), advanced serrated lesion detection rate (ASLDR), and advanced adenoma detection rate (AADR). We included participants who underwent colonoscopy for screening (i.e. those with a positive faecal immunochemical occult blood test – FIT+) or for surveillance after resection of advanced adenomas. We compared both groups using the chi-square and t-Student test.

Results

Between November 2023 and May 2024, we recruited 857 patients, of whom 30 were excluded. The baseline characteristics of the 827 patients included in the analysis were similar (male: 59.3%, screening colonoscopy: 66.7%, mean age: 61.7 ± 6.5 years, withdrawal time: 10:49 ± 04:32 minutes, colorectal cancer incidence: 2.8%). However, there were significant differences between both groups in the Boston Bowel Preparation Scale (conventional colonoscopy: 7.7 ± 1.3 vs. PolyDeep-assisted colonoscopy: 7.4 ± 1.3, p = 0.01). Regarding ADR, we did not find statistically significant differences between conventional and PolyDeep-assisted colonoscopy (57.7% vs. 60.8%, p = 0.4). Similarly, for the secondary endpoints, there were no significant differences in PDR (68.7% vs. 69.6%, p = 0.8), SLDR (32.0% vs. 29.4%, p = 0.5), ASLDR (5.3% vs. 5.1%, p = 1.0), or AADR (24.5% vs. 23.6%, p = 0.8). In Table 1, we described lesion detection rates between both groups by indication (i.e., FIT+ or surveillance).

Conclusion

In the context of expert endoscopists PolyDeep did not increase the ADR.

Introduction

Computer-aided detection (CADe) systems have gained attention for their use in colonoscopy, with growing evidence of increased adenoma detection rates (ADR). However, results remain inconsistent, and debate regarding their usefulness continues, including their impact on serrated lesion (SL) detection and performance across varying levels of endoscopist expertise. Given that CADe is used as a real-time assistive tool, it is crucial to confirm its efficacy in lesion detection before considering long-term outcomes.

Aims & Methods

We conducted a multinational, multicenter randomized controlled trial in the Asia-Pacific (Project CAD/NCCH2217; jRCT1032230396) to assess the efficacy of CADe in improving lesion detection during colonoscopy performed as part of colorectal cancer (CRC) screening [1]. We enrolled asymptomatic individuals aged 50–79 years undergoing either primary screening colonoscopy or colonoscopy following a positive fecal immunochemical test (FIT), who had not received colonoscopy in the past 5 years. Participants were randomly assigned (1:1) to the CADe group (colonoscopy with CADe assistance) or the standard group (colonoscopy without CADe) using a minimization method to balance age, sex, colonoscopy indication, endoscopist experience, and country/region. In the CADe group, approved CADe devices were used in accordance with each country's regulations, including EndoBRAIN-EYE, ENDO-AID, CAD EYE, and WISE VISION. All procedures were performed by endoscopists with experience of ≥500 colonoscopies. The primary endpoint was adenoma detection rate (ADR). Secondary endpoints included adenomas per colonoscopy (APC), advanced ADR (AADR), sessile serrated lesion detection rate (SSLDR), sessile serrated lesions per colonoscopy (SSLPC), scope withdrawal time, and the resection rate of non-neoplastic lesions. Planned sample size was 1400 cases (one-sided α = 0.05, 80% power).

Results

Of the 1,399 participants enrolled between December 28, 2023, and March 6, 2025, 1,373 were included in the full analysis set (688 and 685 in the CADe and standard groups, respectively). In both groups, the proportions of primary screening and post-FIT colonoscopies were 75% and 25%, respectively. No differences were observed between the CADe and standard groups in ADR (54.7% vs. 53.9%; odds ratio [OR] 1.04; 95% confidence interval [CI], 0.83–1.30, one-sided p=0.38), APC (1.17 vs. 1.24; risk ratio [RR], 0.94; 95% CI, 0.81–1.09), or AADR (5.5% vs. 7.6%; OR, 0.71; 95% CI, 0.46–1.10). The CADe group showed higher SSLDR (9.0% vs. 6.0%; OR, 1.55; 95% CI, 1.03–2.33) and SSLPC (0.11 vs. 0.07; RR, 1.65; 95% CI, 1.09–2.50). Subgroup analysis based on endoscopist experience demonstrated a higher SSLDR in the CADe group among those with 500–4,999 (10.1% vs. 5.4%) and 5,000–9,999 (11.9% vs. 3.6%) prior colonoscopies, but not among those with experience of ≥10,000 procedures (7.0% vs. 7.5%). There was no difference between groups in the non-neoplastic lesion resection rate (14.7% vs. 13.4%; OR, 1.11; 95% CI, 0.82–1.50), and the median scope withdrawal time in cases without polypectomy was 9 minutes in both groups.

Conclusion

CADe assistance did not improve adenoma detection where high ADR was already achieved with standard colonoscopy. Nevertheless, it enhanced SSL detection, except among highly experienced endoscopists, without prolonging withdrawal time or increasing unnecessary polypectomies. While our findings do not overstate the efficacy of CADe, they support a reasonable and practical role for its use in improving colonoscopy quality in CRC screening.

References

1. Sekiguchi M, et al. Protocol for a multicenter randomized controlled trial to assess the usefulness of computer-aided detection systems for colonoscopy in colorectal cancer screening in the Asia-Pacific region (project CAD/NCCH2217). Jpn J Clin Oncol. 2025; 55: 837-40.

Disclosure

The authors have no conflict of interest related with this study.

Introduction

Any computer-assisted characterization (CADx) system relies on Artificial Intelligence algorithms to provide a probability score to the endoscopist, characterizing the polyp as an adenoma or a hyperplastic polyp.^1-3 However, the clinical utility of these AI-generated outputs is dependent on the endoscopist’s ability to interpret and integrate them into their final diagnostic decision-making process. This requires not only recognizing and accepting a true positive AI diagnosis, but also accurately identifying and rejecting false positives. This requires a higher level of endoscopist expertise to discern whether an AI-generated classification is accurate and should be incorporated into the final diagnosis or requires correction. The primary challenge in CADx implementation lies in this inherent complexity of human-AI interactions, which can lead to misinterpretation, resulting in the endoscopist either rejecting correct CADx outputs or accepting incorrect classifications, compromising diagnostic accuracy.

Aims & Methods

We conducted a secondary analysis from a prospective study. Endoscopists were first presented with the CADx classification for each polyp, which they could accept or reject and provide an alternative. A total of 1143 patients aged at least 45 underwent colonoscopy between June 2022 and January 2025 at the CHUM Hospital, yielding 753 polyps from 367 patients after exclusion criteria. The primary aim was to assess the agreement/rejection patterns of the CADx diagnosis by the endoscopists, stratified by categorization. Secondary outcomes included the rate at which clinicians correctly rejected inaccurate CADx outputs, as well as trends in post-rejection reclassification.

Results

A total of 89.1% (408/458, 95% CI: (85.8,91.7)) of accepted CADx neoplastic diagnoses were correct, and 68.7% (68/99, 95% CI: (58.5,77.4)) of accepted CADx hyperplastic diagnoses were accurate. However, endoscopists accepted incorrect diagnoses significantly more often when CADx predicted hyperplastic than neoplastic (%, 95% CI: 31.3% (22.6,41.5) vs 10.9% (8.3,14.2)). Regarding the post-rejection patterns, when endoscopists rejected adenoma classifications (N=47), they falsely classified 25 cases (53.2%, 95% CI: (38.2,67.6)) as a sessile serrated lesion/polyp (SSL/P). Similarly, although 43.6% of the rejected hyperplastic CADx predictions were correctly re-assigned an adenoma (31.5%, 95% CI: (24.3,39.7)) or SSL/P diagnosis (12.1%, 95% CI: (7.5,18.7)), there were 41.6% (95% CI: (33.7,50.0)) that were incorrectly re-classified as SSL/Ps.

Conclusion

Endoscopists generally accept accurate adenoma predictions provided by CADx systems but frequently misclassify hyperplastic polyps as SSLs, demonstrating a diagnostic bias toward neoplasia. Although beneficial from a safety perspective, this bias may result in unnecessary early follow-up colonoscopies, increasing associated costs.^4,5 Developing and integrating CADx systems with robust SSL recognition capabilities seems essential to overcome these diagnostic challenges and enhance clinical decision-making when using CADx assisted optical polyp diagnosis. Such advanced CADx systems are likely crucial for successful CADx integration into routine clinical practice.

References

1. Djinbachian R, Taghiakbari M, Barkun A, et al. Optimized computer-assisted technique for increasing adenoma detection during colonoscopy: a randomized controlled trial. Surg Endosc 2025;39:1120-1127.
2. Byrne MF, Von Renteln D, Barkun AN. Artificial Intelligence-Aided Colonoscopy for Characterizing and Detecting Colorectal Polyps: Required, Nice to Have, or Overhyped? Gastroenterology 2023;164:332-333.
3. Taghiakbari M, Mori Y, von Renteln D. Artificial intelligence-assisted colonoscopy: A review of current state of practice and research. World J Gastroenterol 2021;27:8103-8122.à
4. Force AAT, Parasa S, Berzin T, et al. Consensus statements on the current landscape of artificial intelligence applications in endoscopy, addressing roadblocks, and advancing artificial intelligence in gastroenterology. Gastrointest Endosc 2025;101:2-9 e1.
5. Halvorsen N, Barua I, Kudo SE, et al. Leaving colorectal polyps in situ with endocytoscopy assisted by computer-aided diagnosis: a cost-effectiveness study. Endoscopy 2025.

Disclosure

Daniel von Renteln has received research funding from ERBE Elektromedizin GmbH, Ventage, Pendopharm, Fujifilm and Pentax, and has received consultant or speaker fees from Boston Scientific Inc., ERBE Elektromedizin GmbH, and Pendopharm. Roupen Djinbachian has received speaker fees from Fujifilm. The remaining authors declare that they have no conflict of interest.