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

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.

Early Adenocarcinoma Arising from Traditional Serrated Adenoma in the Colon / 대한소화기내시경학회지

A serrated adenoma is a precursor lesion for some cases of microsatellite unstable colorectal carcinoma (CRC). The serrated neoplasia pathway has been associated with carcinogenesis of serrated adenoma, which is different from the traditional adenoma-carcinoma sequence. The serrated neoplasia pathway accounts for 10~15% of CRCs, and these tumors typically demonstrate microsatellite instability. Cases of a CRC arising from a serrated adenoma have been rarely identified with the recent recognition of the serrated neoplasia pathway. However, these cases are not frequently reported in Korea, because this concept has only been recently emphasized. We report a case of an early adenocarcinoma arising from a traditional serrated adenoma of the colon, which was diagnosed and treated by a colonoscopic polypectomy.