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Key messages
Colorectal cancer can occur via more than one molecular pathway. The serrated pathway probably accounts for 20%–30% of colorectal cancer.
Histopathological nomenclature for serrated lesions varies internationally. We suggest the terms hyperplastic polyp (HP), sessile serrated polyp (SSP), and traditional serrated adenoma to describe these lesions.
Colonoscopy is the best detection tool for serrated polyps, but detection rates are variable.
Chromoendoscopy and slower withdrawal time are the only interventions that have been demonstrated to increase serrated lesion detection. High-definition endoscopy and right colon retroflexion may have a role.
All polyps proximal to the recto-sigmoid junction should be removed. A benchmark rate of 4.5% for detection of proximal serrated lesions (HPs plus SSPs proximal to splenic flexure) in screening has been suggested for US-based colonoscopic screening, but implementing a target for serrated lesions in clinical practice is currently impractical.
DNA-based detection significantly augments serrated lesion detection in stool-based screening programmes.
There are limited data to guide surveillance after resection of serrated lesions; however, the logic behind surveillance for serrated lesions is consistent with that for conventional adenomas.
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 …
Footnotes
Contributors All authors contributed equally to the drafting, critical revision and final approval of this manuscript.
Competing interests DKR receives consulting fees from Olympus Corp, America; Endochoice; and Boston Scientific. He receives research support from Olympus Corp, America.
Provenance and peer review Commissioned; externally peer reviewed.