The Diminutive Colon Polyp

Biopsy, Snare, Leave Alone?

Alberto Murino; Cesare Hassan; Alessandro Repici

Disclosures

Curr Opin Gastroenterol. 2016;32(1):38-43. 

In This Article

Abstract and Introduction

Abstract

Purpose of review Diminutive polyps, measuring between 1 and 5 mm, represent the vast majority of colorectal polyps encountered during screening colonoscopy. Although the chance of harboring advanced adenoma or neoplastic cells is low, ensuring a complete polyp resection with clear margins is crucial to reduce the risk of interval colorectal cancer. The purpose of this review was to evaluate the different methods applied for polypectomy of diminutive polyps and clarify whether a diminutive polyp should be retrieved or left in place.

Recent findings Cold biopsy polypectomy is indicated for resection of polyps measuring 1–3 mm and removal of 4–5 mm polyps should be ensured by cold snare polypectomy. Over the last decade, hot biopsy polypectomy has been gradually abandoned because of an increased risk of diathermic injury. The resect and discard strategy and the diagnose and disregard strategy should be performed only by expert endoscopists, who should use validated scales and document the polyp features by storing several endoscopic images.

Summary Nowadays, complete resection of diminutive polyps, following the most appropriate technique, is recommended in clinical practice. The resect and discard strategy and the diagnose and disregard strategy should be reserved to expert endoscopists.

Introduction

It is widely accepted that colonoscopy is the optimal method to detect and manage precancerous lesions.[1,2] Endoscopic detection and resection of colonic polyps is associated with a 77% of reduction in colon cancer incidence and a 29–37% reduction in colon cancer mortality.[3] An adequate adenoma detection rate, which is one of the most important indicators of quality in colonoscopy,[4–5] associated with a complete polyp resection is thus essential to arrest the polyp-cancer sequence. However, colonoscopy is not a perfect method and the occurrence of postcolonoscopy cancers – interval colorectal cancer – cannot be completely excluded,[6,7] essentially because of three factors: missed lesions, de-novo cancer development, and incomplete polypectomy. Back-to-back colonoscopy studies showed that adenoma can be missed in 20–40% of cases[8–10] and 70–80% of postcolonoscopy cancers might be because of either missed cancers or missed adenomas.[11] De-novo cancers are initiated by neoplastic cells that grow faster following a different pathway to cancer possibly because of microsatellite instability.[3,7,11] Finally, 10–27% of postcolonoscopy cancers might be related to incomplete endoscopic resection of colonic polyps.[12] Indeed, obtaining a complete polyp resection with clear margins, irrespective of the size of the polyp, is crucial to reduce the risk of recurrence and/or malignant progression.

Diminutive polyps have a size between 1 and 5 mm, representing the vast majority of colorectal polyps. Ninety percent of polyps encountered during a colonoscopy are sub-centimeter and 10% of them measure between 6 and 9 mm, whereas the remaining 90% are diminutive.[13] Although diminutive polyps are less likely to harbor any advanced histology, published data regarding the presence of high-grade dysplasia are not consistent. Indeed, the prevalence of high-grade dysplasia in colon polyps measuring 1–5 mm in size has been reported between 0.5 and 10%,[14–18] whereas the rate of cancer reported to date has been low and consistent ranging between 0 and 0.05%.[15,17,19] As shown in a recent systematic review[20] based on 20 562 patients undergoing screening colonoscopy, advanced adenomas were detected in 1156 patients (5.6%) and patients with diminutive polyps were the majority of the study population. However, the frequency of advanced adenomas and cancers found in the diminutive polyps resected was low, ranging between 0.9% (132/13 630) and 0.04% (5/13 630), respectively.

Ensuring a complete polyp resection with clear margins even when diminutive polyps are encountered is crucial to reduce the risk of interval colorectal cancer. The resection of diminutive polyps can be performed with cold or hot biopsy forceps or cold polypectomy. The present review focuses on the usefulness, efficacy, and safety of these techniques for resection of diminutive colorectal polyps.

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