[Show abstract][Hide abstract] ABSTRACT: Increasing evidence indicates that colonoscopy offers less reliable protection against proximal versus distal colorectal cancer. Two key factors may explain the occurrence of postcolonoscopy (ie, interval) cancers in the proximal colon, namely endoscopist-dependent factors and biological characteristics of precursor lesions resulting in a more rapid progression. There is increasing evidence that nonpolypoid lesions, of adenomatous or serrated type, are major contributors to interval cancers through endoscopist-dependent factors, as these lesions are preferentially located in the proximal colon and more likely to be overlooked and/or incompletely resected, in particular when predisposing factors (ie, suboptimal bowel preparation or insufficient training) are involved. However, emerging data now indicate that a subset of nonpolypoid adenomas might also display distinct molecular features that may impact on growth as compared with their polypoid counterparts. In this review, we summarize the current literature on classification and biological significance of nonpolypoid colorectal lesions, with special attention to their endoscopic appearance and potential implications for training.
Techniques in Gastrointestinal Endoscopy 04/2013; 15(2):69–76. DOI:10.1016/j.tgie.2012.12.001
"They are also based on the premise that pathological interpretation of the lesions is consistent with the current WHO guidelines as described above. If there is doubt about the latter, a conservative position is to consider all proximal serrated lesions larger than 10 mm as SSAs even if they are reported as HPs . These guidelines were endorsed in a simplified form in the 2012 American Gastroenterological Association guidelines for colonoscopy surveillance after screening and polypectomy . "
[Show abstract][Hide abstract] ABSTRACT: Approximately 30 % of colorectal carcinomas develop via the serrated neoplasia pathway characterized by widespread DNA methylation and frequent BRAF mutation. Serrated polyps represent a heterogeneous group of polyps which are the precursor lesions to serrated pathway colorectal carcinomas. The histological classification of serrated polyps has evolved over the last two decades to distinguish three separate entities: hyperplastic polyp, sessile serrated adenoma (SSA), and traditional serrated adenoma (TSA). The malignant potential of SSAs and TSAs has been clearly demonstrated. SSAs are more challenging to detect by colonoscopy and are likely to account for some interval carcinomas of the proximal colon. Serrated polyposis syndrome is now widely recognized as conferring a high risk of colorectal carcinoma although its cause remains elusive. The current understanding of the actual malignant potential of each serrated polyp subtype is still limited due to the lack of large-scale prospective studies. Patient management guidelines have been recently updated although high-level evidence to support them is still required.
Journal of Gastroenterology 12/2012; 48(3). DOI:10.1007/s00535-012-0720-y · 4.52 Impact Factor
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