776 NOVEL METHOD TO ASSESS COLD SNARE POLYPECTOMY QUALITY FOR 1-10 MM COLORECTAL POLYPS – MEASURING THE MINIMUM EXTENT OF A HEALTHY RESECTION MARGIN

Abstract

Measuring quality of polypectomy in clinical practice remains a challenge. We examined the extent of a normal healthy tissue margin around neoplastic tissue of the resected polyp specimen as a potential quality marker for polypectomy. Prospective single center study in patients who underwent an elective outpatient colonoscopy with non-cautery (cold) polyp resection between July 2017 and September 2019. All non-fragmented polyps were included in the analysis. Patient and polyp characteristics, and resection methods were prospectively documented on predefined case report forms. To control for snare type, all snares were rotated monthly (one snare type each month). The healthy margin was defined as the difference between the resected specimen size and the neoplasia size (serrated or adenomatous; measured by the pathologist) divided by two. We assessed the healthy margin across endoscopists, by type of snare (dedicated cold snare vs standard snare), and by polyp characteristics. 561 patients (mean age 65) with 1724 polyps were included in the analysis. The mean size as estimated by the endoscopist was 4.0 mm (median 4 mm). This estimate was approximately 50% greater than the measured neoplasia size of 2.6 mm (median 2.0 mm). The healthy margin varied across endoscopists from 0.8 to 1.4 mm (p<0.001), with an almost 2-fold variation in the proportions of polyps with a minimum helathy margin of ≥1 mm (29% to 57%, (p<0.001). Attending-gastroenterologists resected polyps with a wider margin than trainees (p<0.001). Dedicated cold snares achieved a larger resection margin than standard snares (1.4 vs 1.0 mm, p<0.001), and removed a greater proportion of polyps with a margin ≥1mm (56% vs 39%, p<0.001). There was no difference in the extent of the healthy margin by polyp size, proximal location, or histology. The study examined the healthy tissue margin surrounding polyp neoplasia as a potentially novel quality marker for polyp resection. The margin varied two-fold across endoscopists, in particular between attendings and trainees, and was larger when dedicated cold snares were used. The findings encourage future validation of this new measure.Figure 1Variation of mean minimum healthy margin across endoscopistsView Large Image Figure ViewerDownload Hi-res image Download (PPT)