1560 Sessile Serrated Polyposis Syndrome (SPS) and Sessile Serrated Polyps (SSPs): Features, Variations in Detection Rate, and the Associated Risk of Both Synchronous and Metachronous Neoplasia

Abstract

INTRODUCTION: Colorectal cancer (CRC) is the second most common cancer worldwide, accounting for 8% of all cancer related deaths. Sessile serrated polyposis syndrome (SPS) is a genetically inherited disease. The actual prevalence is unknown but is estimated to be 1 in 2000 to 3000 CASE DESCRIPTION/METHODS: 63 year old female with no family history of colon cancer, presented for a diagnostic colonoscopy after a positive fecal occult blood test (FOBT). FOBT was done for screening purposes. Patient had a negative FOBT X 3 a year ago. Colonoscopy showed 10 polyps. All polyps were resected with different techniques based on size, features and location. All polyps came back as sessile serrated polyps. 6 polyps showed features of cytologic dysplasia. 5 were proximal to the Sigmoid colon (1 was >20 mm in size and 3 were >10 mm in size). DISCUSSION: Based on a growing body of data, sessile serrated polyps (SSPs) have a higher prevalence than previously thought. Whether sporadic or part of the sessile serrated polyposis syndrome (SPS), SSPs are associated with increased risk of synchronous and metachronous neoplasia. A recent study looked at the synchronous burden of large (≥ 20 mm) SSPs in patients without SPS. The study found that 67/146 patients (45.9 %) had SPS, 53/146 (36.3 %) had a solitary SSP, and 26/146 (17.8 %) were categorized as oligo-SSP. Dysplasia in large SSPs was frequent in all groups (41.1 % overall). SPS was recognized by referring endoscopists in only 9.0 % of cases. Patients meeting the World Health Organization criteria who elect long-term endoscopic surveillance should receive annual colonoscopy after the diagnosis is established. Surgery is indicated when CRC is diagnosed or the number of polyps makes endoscopic control unfeasible. White-light endoscopy is considered the gold standard for detection and removal of colorectal lesions to prevent CRC development. However, detection of small adenomas (<5 mm) and SSPs is difficult as conventional endoscopy relies on the experience of the endoscopist. As a result, the reported adenoma detection miss rate for the general population is relatively high (27%). This underscores the necessity of improving endoscopic detection strategies. In a randomized controlled trial, 86 patients with SPS underwent tandem high-definition (HD) colonoscopies from February 2015 through July 2016 at 7 centers in Spain. It was found that panchromoendoscopy increases detection of polyps (mostly of small serrated lesions) and should be considered in patients with SPS.