Colorectal polyp classification and management of complex polyps for surgeon endoscopists

Abstract

Increasing familiarity with advanced endoscopic excision techniques allows for more colorectal lesions to be removed without major surgery. Endoscopic excision with negative margins is adequate for most polyps and low-risk T1 cancers. The use of modern polyp classification techniques based on size, morphology and pit pattern by an experienced endoscopist allow for an optical diagnosis of these lesions and can predict, with high accuracy, which lesions contain malignant disease and the level of invasion. A surgeon endoscopist must be able to recognize which complex polyps can be resected with advanced polypectomy techniques and which require upfront surgery. We aimed to provide an overview of polyp classification techniques to help surgeons select the correct treatment algorithm for advanced colorectal lesions based on their visual characteristics at index endoscopy.

Fig. 1

Schematic representation of the Paris classification of polyp morphology. M = mucosal layer; SM = submucosal layer.

Fig. 2

Lateral spreading tumour classification. Reused from Kudo S ei, Lambert R, Allen JI, et al. Nonpolypoid neoplastic lesions of the colorectal mucosa. Gastrointest Endosc 2008;68(4 Suppl):S3–S47, with permission from Elsevier.

Fig. 3

The Narrow-Band Imaging International Colorectal Endoscopic (NICE) Classification. Reused from Hayashi N, Tanaka S, Hewett DG, et al. Endoscopic prediction of deep submucosal invasive carcinoma: validation of the narrow-band imaging international colorectal endoscopic (NICE) classification. Gastrointest Endosc 2013;78(4):625–32, with permission from Elsevier. NBI = narrow-band imaging.

Fig. 4

The Japan NBI Expert Team (JNET) classification subdivision of NICE type 2 polyps. Reused from Kobayashi S, Yamada M, Takamaru H, et al. Diagnostic yield of the Japan NBI Expert Team (JNET) classification for endoscopic diagnosis of superficial colorectal neoplasms in a large-scale clinical practice database. United European Gastroenterol J 2019;7:914–23, with permission from John Wiley & Sons Inc. NBI = narrow-band imaging; NICE = Narrow-Band Imaging International Colorectal Endoscopic Classification.

Fig. 5

Kudo colonic pit pattern classification. Reused from Tanaka S, Kaltenbach T, Chayama K, et al. High-magnification colonoscopy (with videos). Gastrointest Endosc 2006;64:604–13, with permission from Elsevier.

Fig. 6

Decision aid for when a polyp is discovered at endoscopy. *These lesions should be tattooed just distal, ensuring that tattoo material does not touch the lesion. †If the endoscopist cannot confidently and completely remove the polyp, they should not attempt and refer. As always, treatment should be individualized accounting for patient factors and the skill set of the surgeon endoscopist.