COMPARISON OF DRUGS FOR EOSINOPHILIC ESOPHAGITIS: SYSTEMATIC REVIEW AND NETWORK META-ANALYSIS

UEG Presentation

HISTOLOGICAL RISK STRATIFICATION FOR LYMPH NODE METASTASIS IN PT2 RECTAL CANCER AFTER LOCAL EXCISION: A MULTICENTRE INTERNATIONAL STUDY

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Introduction

Local excision (LE) is increasingly used to treat early rectal cancer (cT1-2N0M0), but its role in pT2 cancer remains controversial due to a reported 20–30% risk of lymph node metastasis (LNM). Since this risk is largely linked to adverse histological features, patients without these risk factors may safely avoid completion total mesorectal excision (cTME). We aimed to refine LNM risk in pT2 rectal cancer following LE to better guide decisions on rectal-preserving treatment strategies.

Aims & Methods

Patients with pT2 rectal cancer who underwent en bloc LE for cT1-2N0M0 lesions were retrospectivelly enrolled from seven international centres (2015-2025). Eligible patients received either cTME or active surveillance with MRI follow-up for at least two years. Exclusion criteria were positive resection margins (<0.1mm), synchronous or recurrent colorectal cancer and (neo)adjuvant therapy. LNM were confirmed through TME histology or considered absent when no suspicious lymph nodes appeared on follow-up MRI. A detailed histological review of LE specimens was conducted by specialised pathologists at each participating centre using a standardised protocol. Assessed risk factors included high-grade differentiation and/or mucinous subtype, lymphovascular invasion (small and/or large vessels), tumour budding grade 2-3 and/or poorly differentiated clusters grade 2-3, and perineural invasion. Primary endpoint was LNM rate in patients without histological risk factors. Secondary endpoints included the association between individual risk factors and LNM, as well as locoregional recurrences during active surveillance.

Results

A total of 103 patients (mean age 66 (SD 10), 56% male) with a median lesion size of 25mm (IQR 15) were included. Endoscopic LE was performed in 31 patients (30%) and surgical LE in 72 (70%). After LE, 76 patients (74%) underwent cTME while 27 (26%) opted for active surveillance. The overall LNM rate was 17.5% (18/103). Among the 36 patients (35%) without histological risk factors, the LNM rate was 5.6% (2/36; OR 0.19, 95% CI 0.04-0.87, p=0.032). Both LNM cases were detected in the cTME group. LNM rates per individual risk factor are presented in Table 1.
In the active surveillance group, no locoregional recurrences occurred in the ten patients without risk factors during a median follow-up of 53 months (IQR 26). Among patients with risk factors, two of 14 patients with one risk factor developed a locoregional recurrence and one of two patients with two risk factors. All recurrences occurred intramurally following prior surgical LE. The only patient with three risk factors had no locoregional recurrence but died from unrelated cause at 24 months.

Table 1. Univariate analyses of histological risk factors for lymph node metastasis

Risk factor	n/N (%)	Lymph node metastasis rate (%)	Odds ratio (95% CI)	P-value
No histological risk factors	36/103 (35.0)	2/36 (5.6)	0.19 (0.04-0.87)	0.032
Lymphovascular invasion Small vessel invasion Large vessel invasion	47/103 (45.6) 32/103 (31.1) 28/103 (27.2)	12/47 (25.5) 11/32 (34.4) 4/28 (14.3)	7.0 (2.2-21.8) 4.3 (1.5-12.5) 7.5 (2.4-23.3)	0.055 0.004 0.604
Tumour budding and/or poorly differentiated clusters grade 2-3 Tumour budding grade 2-3 Poorly differentiated clusters grade 2-3	36/103 (35.0) 29/103 (28.2) 19/103 (18.4)	13/36 (36.1) 10/29 (34.5) 9/19 (47.4)	7.0 (2.2-21.8) 4.3 (1.5-12.5) 7.5 (2.4-23.3)	<0.001 0.007 <0.001
Adverse histology Poor tumour differentiation Mucinous subtype	13/103 (12.6) 7/103 (6.8) 6/103 (5.8)	6/13 (46.2) 3/7 (42.9) 3/6 (50.0)	5.6 (1.6-19.4) 4.1 (0.8-20.0) 5.5 (1.0-29.7)	0.007 0.086 0.049
Perineural invasion	11/103 (10.7)	5/11 (45.5)	5.1 (1.3-19.0)	0.016

Conclusion

In this group of pT2 rectal cancer patients treated with LE, detailed histological analysis suggests a low LNM risk (5.6%) in patients without histological risk factors. No locoregional recurrences occurred in this low-risk group during active surveillance. As 35% of pT2 rectal cancers lacked histological risk factors, a risk-stratified approach could potentially allow a substantial proportion of patients to avoid cTME. Prospective validation in larger cohorts is needed before clinical implementation.

HISTOLOGICAL RISK STRATIFICATION FOR LYMPH NODE METASTASIS IN PT2 RECTAL CANCER AFTER LOCAL EXCISION: A MULTICENTRE INTERNATIONAL STUDY

1 Amsterdam University Medical Center, Amsterdam, Netherlands

2 University Medical Center Utrecht, Utrecht, Netherlands

3 IJsselland Hospital, Capelle aan de IJssel, Netherlands

4 Flevo Hospital, Almere, Netherlands

5 OLVG, Amsterdam, Netherlands

6 Elisabeth-TweeSteden Hospital, Tilburg, Netherlands

7 IRCCS Humanitas Research Hospital, Milan, Italy

8 University Hospital Leuven, Leuven, Belgium

Event

UEG Week Berlin 2025

Topics

Colorectal Digestive Oncology Endoscopy Histopathology

Submission format

Late-Breaking Abstract

Session

Colorectal ESD: The better way?

Citation

United European Gastroenterology Journal 2025; 13 (Supplement 8)

Published

2025

UEG Presentation

COMPUTER AIDED QUALITY CONTROL SYSTEM IMPROVES BARRETT’S NEOPLASIA DETECTION IN AN EX-VIVO SETTING

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Introduction

Early detection of neoplasia in Barrett’s Esophagus (BE) remains challenging. Although computer-aided detection (CADe) systems are increasingly available to support endoscopists, successful CADe implementation largely depends on the quality of endoscopic images, which can vary significantly in clinical practice. This study introduces an innovative computer-aided quality (CAQ) system designed for BE endoscopy, capable of assessing various image quality parameters, providing real-time feedback to the endoscopist, and operating in conjunction with an established CADe system.

Aims & Methods

The CAQ system was trained on 4,926 images from 243 BE patients to assess both objective (e.g., blurriness, illumination, and specular reflections) and subjective (i.e., mucosal cleanliness and esophageal expansion) image quality factors. The system is able to provide real-time feedback on these quality parameters to the endoscopist. Additionally, it is configured to function as a preprocessing filter for a previously developed CADe system, automatically excluding lower-quality images. To validate the CAQ system’s performance as a standalone tool, we constructed an endoscopic image quality test set, which included 647 images from 51 non-dysplastic BE patients across eight hospitals. These images were annotated for objective (e.g. motion blur, lighting) and subjective (i.e. esophageal expansion, mucosal cleanliness) image quality parameters by two experts. Additionally, to evaluate the CAQ system’s role as a preprocessing step for an established CADe system, we created the Barrett CADe test set, containing 956 frames from 62 neoplastic BE patients and 557 frames from 35 non-dysplastic BE patients from 12 Barrett referral centers. Outcome measures included agreement scores with experts for standalone image quality assessment and sensitivity, specificity, and Area-under-the-Curve (AUC) for BE neoplasia detection.

Results

As a stand-alone system, the CAQ system achieved Cohen’s Kappa scores for agreement with expert annotators of 0.73, 0.91, and 0.89 for objective image quality parameters, mucosal cleanliness, and esophageal expansion, respectively—comparable to inter-annotator scores of 0.73, 0.93, and 0.83. When used as a preprocessing filter for the CADe system, the CAQ system improved the CADe's sensitivity from 82% to 90% and the AUC from 87% to 91%, while specificity remained stable at 75% (Table 1).

Table 1. Performance of the CADe system for Barrett’s neoplasia detection with and without the CAQ system.

Evaluated by	Sensitivity, %, (95% CI)	Specificity, %, (95% CI)	AUC, %, (95% CI)
CADe	82.2 (79.7 - 84.5)	74.7 (70.9 - 78.1)	87.2 (79.9 - 94.5)
CAQ + CADe	89.9 (87.2 - 92.1)	74.7 (70.0 - 78.9)	91.4 (82.0 - 100)

Conclusion

This study introduces the first CAQ system specifically aimed at automated quality control in BE endoscopy. As a standalone tool, the system effectively distinguishes poorly from well-visualized mucosa. When combined with an established CADe system, it enhances detection rates for neoplasia, highlighting its potential to improve diagnostic accuracy in BE surveillance.