Optimal Endoscopic Treatment and Surveillance of Serrated Polyps

Abstract

Serrated polyps are considered precursor lesions that account for 15% to 30% of colorectal cancers, and they are overrepresented as a cause of interval cancers. They are difficult to detect and resect comprehensively; however, recent data suggest that high definition endoscopy, chromoendoscopy (via spray catheter, pump or orally), narrow band imaging, split-dose bowel preparation and a slower withdrawal (>6 minutes) can all improve detection. Cold snare resection is effective and safe for these lesions, including cold snare piecemeal endoscopic mucosal resection, which is likely to become the standard of care for lesions >10 mm in size. Sessile serrated lesions ≥10 mm in size, those exhbiting dysplasia, or traditional serrated adenomas increase the chance of future advanced neoplasia. Thus, a consensus is emerging: a surveillance examination at 3 years should be recommended if these lesions are detected. Serrated lesions likely carry equivalent risk to adenomas, so future guidelines may consider serrated class lesions and adenomas together for risk stratification. Patients with serrated polyposis syndrome should undergo surveillance every 1 to 2 years once the colon is cleared of larger lesions, and their first degree relatives should undergo screening every 5 years starting at age 40.

Keywords: Colorectal neoplasms; Endoscopic mucosal resection; Endoscopic submucosal dissection; Serrated polyposis syndrome; Serrated polyps.

Fig. 1

Workgroup on Serrated Polyps and Polyposis (WASP) classification.

Fig. 2

Cold snare lift and endoscopic mucosal resection of small sessile serrated lesion. (A) A 5-mm serrated polyp observed in the ascending colon. (B) Lesion seen with narrow-band imaging under magnification; note the small black dots within the pits, suggestive of a sessile serrated lesion. (C) Resected lesion with fluid. The specimen was stained with methylene blue as a contrast agent to clarify the lesion edges. (D) Lesion grasped with a thin wire cold snare. Note the additional normal mucosa snared to ensure complete excision. (E) Post-resection defect observed under magnification after washing. Note that normal mucosa can be clearly observed around the edges, confirming excision.