Sessile serrated polyps: cancer risk and appropriate surveillance.

■ ABSTRACT Sessile serrated polyps are a recently recognized type of neoplastic polyp that develops along a molecular pathway different from that of conventional adenomas. While the clinical significance of the serrated pathway to colorectal cancer is clear, further study is needed to un- derstand a patient's lifetime colorectal cancer risk posed by serrated neoplasms and the optimal postpolypectomy surveillance interval. ■ ■ KEY POINTS From 20% to 30% of colorectal cancers arise through the serrated polyp pathway (the serrated neoplasia pathway.) Histologically, serrated polyps have a serrated or saw- tooth appearance from the folding in of the crypt epithe- lium. Types of serrated polyps include hyperplastic polyps, traditional serrated adenomas, and sessile serrated polyps (also known as sessile serrated adenomas). Guidelines for surveillance after polypectomy of serrated lesions recommend that patients with a large (≥ 10-mm) or a sessile serrated polyp with cytologic dysplasia or a traditional serrated adenoma be followed more closely than patients with a sessile serrated polyp smaller than 10 mm. Patients with small rectosigmoid hyperplastic polyps should be followed the same as people at average risk.