Serrated Lesions in Colorectal Cancer Screening

Detection, Resection, Pathology and Surveillance

James E East; Michael Vieth; Douglas K Rex

Disclosures

Gut. 2015;64(6):991-1000. 

In This Article

Abstract and Introduction

Introduction

A strong evidence base supports colorectal cancer screening. Interruption of the adenoma-carcinoma sequence by endoscopic polypectomy has been considered the key step in preventing the development of colorectal cancer.[1] Higher adenoma detection rates (ADR) at colonoscopy have a linear correlation with lower postcolonoscopy colorectal cancer (PCCRC) rates and death from PCCRC.[2] However, colonoscopy is not as effective in prevention of colorectal cancer in the right colon as in the left.[3–5] Interval cancers are often right-sided and hypermethylated, not consistent with an origin in conventional adenomas.[4] Recent molecular approaches to colorectal cancer indicate there are three or more distinct molecular pathways to colorectal cancer, including a pathway arising through serrated lesions.[6,7]

Serrated lesions pose multiple challenges in clinical practice, particularly with regard to detection. Sessile serrated polyps (SSP), the most important subset of the serrated class of lesions, are endoscopically subtle lesions distributed predominantly in the right colon. SSPs are often flat and have minimal discolouration when compared with the background mucosa. These lesions are challenging to detect by any method, including colonoscopy. SSPs are also more challenging to completely resect using standard polypectomy techniques compared to conventional adenomas.[8] Finally, there are few observational data to guide development of postpolypectomy surveillance guidelines after resection of serrated lesions.

In this review, we aim to clarify for clinicians the role of serrated lesions in colorectal cancer screening, and the practical issues that flow from our current understanding of their importance.

processing....