Characteristics and outcomes of endoscopically resected colorectal cancers that arose from sessile serrated adenomas and traditional serrated adenomas

Abstract

Background/aims: The efficacy and safety of endoscopic resection of colorectal cancer derived from sessile serrated adenomas or traditional serrated adenomas are still unknown. The aims of this study were to verify the characteristics and outcomes of endoscopically resected early colorectal cancers developed from serrated polyps.

Methods: Among patients who received endoscopic resection of early colorectal cancers from 2008 to 2011, cancers with documented pre-existing lesions were included. They were classified as adenoma, sessile serrated adenoma, or traditional serrated adenoma according to the baseline lesions. Clinical characteristics, pathologic diagnosis, and outcomes were reviewed.

Results: Overall, 208 colorectal cancers detected from 198 patients were included: 198 with adenoma, five with sessile serrated adenoma, and five with traditional serrated adenoma. The sessile serrated adenoma group had a higher prevalence of high-grade dysplasia (40.0% vs. 25.8%, P<0.001) than the adenoma group. During follow-up, local recurrence did not occur after endoscopic resection of early colorectal cancers developed from serrated polyps. In contrast, two cases of metachronous recurrence were detected within a short follow-up period.

Conclusions: Cautious observation and early endoscopic resection are recommended when colorectal cancer from serrated polyp is suspected. Colorectal cancers from serrated polyp can be treated successfully with endoscopy.

Keywords: Colonic polyps; Colonoscopy; Colorectal neoplasms; Sessile serrated adenoma; Traditional serrated adenoma.

Fig. 1. Colonoscopic and histologic pictures of polyps in patient 1. (A) PET-CT image shows signal intensity in the mid transverse colon (arrow). (B) Colonoscopic features of colorectal cancer (CRC) developed from sessile serrated adenoma (SSA). (C) Histologic features of CRC (white circle) developed from SSA (black circle) (H&E, ×100).