Early Lesions Seen in Colonoscopic Surveillance Biopsies from Regions where Colorectal Carcinoma Developed in Patients with Inflammatory Bowel Diseases are Often Not Overtly Dysplastic

BACKGROUND & AIMSScreening for precancerous lesions by colonoscopic surveillance in patients with longstanding inflammatory bowel disease (IBD) has been a standard practice. However, failure of detecting precursors and preventing colorectal carcinoma (CRC) development is still common. This study aims to assess whether some lesions shown in the surveillance biopsies eluded our attention due to atypical histopathology. METHODS91 patients (M 67/F 24, UC 59/CD 32) with surgically resected IBD-CRC were retrieved from 2 institutions in North America over 20 years. 40 patients with [≥]1 colonoscopies performed >1 year prior to cancer diagnosis were regarded as "surveillanced". Pathology records of CRC resections and all prior colonoscopic biopsies were reviewed. RESULTS87.5% of these patients had [≥]1 lesion detected in prior biopsies. Index lesion, the first lesion identified in all the biopsies, was detected in 65% of patients and in 86.8% of the regions where carcinoma developed later, in which 38.2% were conventional low-grade dysplasia (LGD), 29.4% indefinite for dysplasia (IND), 29.4% inflammatory polyp (IP), and 2.9% serrated lesions (SL). CONCLUSIONIn patients who had surveillance, certain lesions were detected by endoscopic biopsies in >80% of patients. >60% of index lesions were not overtly dysplastic, including IND, IP and SL, which may in part represent colitis-associated non-conventional dysplastic lesions.