We aim to compare the estimation of polyp size using the visual estimation of colon polyp with or without the open biopsy forceps technique against actual polyp size measurement by our histopathology department for all polyps >1 cm in size.

A single centre, retrospective analysis of 47 consecutive patients who have had polypectomies done for polyps >1 cm in size from April 2024 at a hospital in North London. The data was collected using the Medilogic endoscopy reporting tool and the electronic patients record. The size of the polyps documented in the endoscopy report was then compared to the lab measured actual polyp size.

25/47 (53%) polyps greater than 1cm had similar histological size to endoscopic size estimate. 22/47 (47%) of polyps greater than 1cm had poor correlation of size with histology, of which 21 had size overestimated at endoscopy in comparison to histology.

Colon polyp size is a critical biomarker for clinical management of colonic polyps. Larger polyps have a greater malignant potential. During colonoscopy, it is important to correctly measure the size of the polyps because of the direct correlation of size with colon cancer and defining a polyp as high-risk polyp which aids appropriate further surveillance colonoscopy. During polypectomy, size of the colonic polyps encountered are often gauged by visual estimation or the open forceps method. However, some data exists on the questionable reliability of a visual estimate even amongst expert colonoscopists.

From this study, we can conclude that visual estimation of polyp size at endoscopy is inaccurate with wide variations between the reported size and the actual size of the polyps. Accurate measurement of colonic polyps is important as inaccuracies can lead to potentially larger polyps not being tattooed and patients with smaller polyps having to attend for subsequent surveillance colonoscopy when they could have been safely discharged as per current ESGE guidelines. We advocate that the ‘gold standard’ practice of direct measurement of the polyp once excised and outside the body be adopted and this be used to guide subsequent management.