The Significance of Sessile Serrated Polyps in Inflammatory Bowel Disease

Background: The significance of serrated lesions in inflammatory bowel disease (IBD) remains unclear. We aim to characterize synchronous and metachronous lesions in IBD patients with an index serrated polyp and compare them to sporadic subjects with SSP. Methods: Serrated lesions in patients with IBD were identified from a pathology database and, after review, were reclassified as hyperplastic (HP), sessile serrated (SSPs), or serrated polyps unclassifiable (SPU). Results: One hundred thirty-four IBD patients were found to have 147 serrated polyps at index colonoscopy. SSPs were more likely to be located in the right colon: SSP (76.0%), SPU (41.7%) and HP (27.8%); P = 0.002. Synchronous multifocal visible dysplasia occurred more frequently in the SSP or SPU groups (44.5% and 66%) compared to the HP group (12%); P = 0.031. Among 13 IBD patients with index SSP followed over a median of 6 years, 61.5% developed metachronous visible dysplasia or additional SSPs. Larger index SSP size was associated with higher risk of developing subsequent visible dysplasia with a 10% increase for every 1 mm increase in size (HR = 1.1; P = 0.028), but was not associated with developing subsequent SSP (P = 0.50). The risk of subsequent SSP or visible dysplasia was no different between the IBD and non-IBD groups, but there was a trend suggesting SSP may be a marker of increased early risk of metachronous visible dysplasia in IBD patients. Conclusions: IBD patients with an index SSP and SPU have a heightened risk of synchronous multifocal visible dysplasia. Additionally, IBD patients with SSP may be at risk of early metachronous visible dysplasia.