The understanding of the underpinnings of such interval CRCs is of importance because it may permit identification of modifiable factors, for example gaps in knowledge and training on the recognition of nonpolypoid neoplasms and their endoscopic resection. In this case, tailored educational programs would improve the awareness and help to shape practical skills, to ultimately safeguard the quality of colonoscopy. Furthermore, it is important to understand whether

certain molecular features of the inflamed mucosa could augment the risk of cancer progression. Such information may help to develop personalized (ie, molecular-based) surveillance strategies. Two recent studies exploring the cause of sporadic interval CRCs in the general population found missed lesions represent by far the most important contributor (>50% of all interval CRCs).22 and 23 ABT-199 cell line VX-809 price Undoubtedly, missed lesions are likely to account for a significant proportion of interval CRCs in IBD, although a thorough analysis using structured algorithms24 has not yet been performed. A recent population-based analysis by Wang and colleagues,25 using SEER

cancer registry data from 55,008 older patients with CRC, found rates of early/missed CRCs were three-fold greater in IBD than in patients without IBD (15.1% for Crohn’s disease, 15.8% for UC vs 5.8% for patients without IBD; P<.001). Early/missed CRCs were defined as CRCs identified within 6 to 36 months after a colonoscopic examination that did not detect cancer. This study was based on administrative data, and therefore lacked detail about the completeness of colonoscopy, bowel preparation, extent of colitis, characteristics of mucosal lesions identified at the baseline examination, and resection outcomes. Such observations underscore the importance of meticulous inspection of the entire colonic mucosa, which should be ideally clean and free of inflammation, and the need for formal training of

the endoscopist in the recognition of IBD neoplasms. Presence of active Phosphatidylinositol diacylglycerol-lyase or chronic background inflammation and the diversity in endoscopic appearance of dysplasia by IBD may, however, increase the complexity of diagnosis. Fig. 1 illustrates a lateral spreading tumor of granular subtype, which could have been missed at a previous examination. A substantial number of studies demonstrated that indigo carmine– or methylene blue–guided chromoendoscopy (CE) improves the diagnostic yield of dysplasia and invasive CRC during IBD surveillance. This is not surprising, because a significant proportion26, 27 and 28 of dysplastic lesions in patients with IBD appear to have a flat appearance, as illustrated in Table 1. Pancolonic CE delineates the borders and permits a detailed analysis of the epithelial surface, thus facilitating the diagnosis of subtle lesions and their endoscopic resection.