A159 RISK OF TOTAL METACHRONOUS ADVANCED NEOPLASIA IN PATIENTS WITH SERRATED LESIONS AND INFLAMMATORY BOWEL DISEASE

Background

The risk of total metachronous advanced neoplasia (TMAN) in patients with serrated lesions (SL) and IBD is unknown. It is also unclear whether colonic inflammation in IBD contributes to serrated neoplasia.

Purpose

Study aim was to compare the risk of TMAN at surveillance colonoscopies in patients with SL and IBD to patients with SL without IBD. We also sought to compare IBD severity in patients with IBD and SL in a colonic area involved with IBD (SL-IA) to patients with IBD and SL in an uninvolved area (SL-UA).

Method

A cohort study was conducted. Through pathology database search, we identified 2428 patients with endoscopically resected SL, defined as sessile serrated lesion (SSL), traditional serrated adenoma (TSA) or IBD and serrated epithelial change (SEC), between 2010 and 2019 at the University of Montreal Hospital Center. We included patients aged 45-75 without polyposis syndromes and excluded patients with a history of CRC, first surveillance <12 months after complete index, sigmoidoscopy at index, or no follow-up. Patient files were reviewed for demographic data, IBD severity, and findings at index and follow-up. Follow-up was continued until TMAN or last colonoscopy within 10 years. Primary outcome was the risk of TMAN (defined as advanced adenoma (AA), advanced serrated lesion (ASL) or CRC) in a surveillance colonoscopy within 10 years from index. Secondary outcomes were the risk of metachronous AA and ASL, and IBD severity in SL-IA and SL-UA. Continuous and categorical variables were compared using the student t, Pearson’s chi-squared, or Mann-Whitney tests. We performed univariate and multivariate Cox regressions, with hazard ratios (HR) and 95% confidence intervals.

Result(s)

In the metachronous outcomes analysis, 440 patients with SL (mean age 61.8 y., 51.6% male, 424 SSL, 16 TSA) were eligible, and 37 with SL and IBD were eligible (mean age 60.9 y., 54.1% male, 30 SSL, 6 SEC, 1 TSA). Compared to patients without IBD, IBD patients were less likely to have synchronous adenomas (16.2% vs 41.6%, p<0.05), had less SLs ≥10 mm (24.3% vs 46.8%, p<0.05), and had a similar risk of metachronous TMAN (HR=0.92 [0.44–1.90]), AA (HR=0.53 [0.13–2.12]) and ASL (HR=1.03 [0.44–2.41]). In the comparison of SL-UA and SL-IA, 56 patients with IBD were eligible, with 21 having SL-UA (mean age 62.0 y., 42.9% male, 19 SSL, 1 TSA, 1 SEC) and 35 having SL-IA (mean age 60.8 y., 62.9% male, 27 SSL, 1 TSA and 8 SEC). Both groups had similar time intervals between IBD diagnosis and SL diagnosis (p>0.05), and similar maximal therapeutic maintenance steps (p>0.05), as well as Mayo/SES-CD scores, serum C-reactive protein, hemoglobin, and albumin, and fecal calprotectin values at index and last colonoscopy (p>0.05).

Conclusion(s)

Patients with SL and IBD are not at higher risk of total metachronous advanced neoplasia than patients with SL and no IBD. SLs in IBD should be considered sporadic and undergo endoscopic resection and follow-up similar to non-IBD patients.

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CIHR, Other

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Fonds de Recherche du Québec en Santé

Disclosure of Interest

None Declared

A106 COMPARING SIZE MEASUREMENTS OF SIMULATED COLORECTAL POLYPS SIZE AND MORPHOLOGY GROUPS WHEN USING A VIRTUAL SCALE ENDOSCOPE OR VISUAL SIZE ESTIMATION: A BLINDED RANDOMIZED CONTROLLED TRIAL

Background

The polypectomy technique used to remove colorectal polyps is influenced by the size of the polyp. Furthermore, the criteria for assigning surveillance intervals after polypectomy are based on size and pathology results. Visual size assessment is potentially fraught with being inaccurate. The virtual scale endoscope (VSE) allows projection of a virtual scale onto colorectal polyps allowing real-time size measurements.

Purpose

We studied the relative accuracy of VSE compared to visual assessment (VA) for the measuring simulated polyps of different size and morphology groups.

Method

We conducted a blinded randomized controlled trial using simulated polyps imbedded within a colon model. Sixty simulated polyps were created and evenly distributed across four different size groups (0-4.9 mm, 5-9.9 mm, 10-19.9 mm and ≥ 20 mm) and 3 different Paris morphology groups (flat, sessile and pedunculated). Six endoscopists (3 staff gastroenterologists and 3 trainees) performed size measurements of all sixty simulated polyps using random allocation of either VA or VSE.

Result(s)

A total of 359 measurements were completed. The relative accuracy of VSE was significantly higher when compared to VA for polyps ≥ 5 and <10mm, ≥ 10 and <20mm, ≥ 20mm (p=0.004; p<0.001, p<0.001). For polyps <5mm, the relative accuracy of VSE compared to VA was nominally higher (79.4% versus 74.1%) but this was not statistically significant (p = 0.186). The relative accuracy of VSE was higher when compared to visual assessment for sessile (p = 0.001), flat (p < 0.001) and pedunculated polyps (p = 0.002). VSE misclassified a lower percentage of ≥ 5 mm polyps as < 5 mm (2.9%), ≥ 10 mm polyps as < 10 mm (5.5%) and ≥ 20 mm polyps as < 20 mm (21.7%) compared to visual estimation (11.2; 24.7 and 52.3% respectively; p=0.008, p<0.001 and p=0.003).

Conclusion(s)

VSE had significantly higher relative accuracies for every polyp size group or morphology type aside from diminutive where VSE had a non-significantly higher relative accuracy. VSE enables endoscopist to better classify polyps into correct size categories at clinically relevant size thresholds of 5-, 10- and 20-mm. Implementing VSE as a standard measurement tool could allow improving clinical decision making for accurate surveillance interval assignment and choice of polypectomy technique.

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Other

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The study was supported by a "Fonds de Recherche du Québec Santé" career development award (Daniel von Renteln) and a University of Montreal student award “PRogramme d’Excellence en Médecine pour l’Initiation En Recherche – PREMIER (Claire Haumesser).

Disclosure of Interest

C. Haumesser: None Declared, M. Zarandi-Nowroozi: None Declared, M. Taghiakbari: None Declared, R. Djinbachian: None Declared, M. Abou Khalil: None Declared, S. Sidani: None Declared, J. Liu: None Declared, B. Panzini: None Declared, I. Popescu Crainic: None Declared, D. von Renteln Grant / Research support from: ERBE Elektromedizin GmbH, Ventage, Pendopharm, Fuji and Pentax, Consultant of: Boston Scientific Inc., ERBE Elektromedizin GmbH, and Pendopharm