OC-054 Development and Validation of a Classification System to Identify Barrett’s Neoplasia Using Acetic Acid Chromoendoscopy: The Predict Classification

Introduction Neoplasia in Barrett’s can be discrete and patchy. Acetic acid chromoendoscopy (AAC) has been demonstrated to highlight neoplastic areas allowing for earlier treatment. Previous efforts to create a classification system for AAC have not been systematic and rigorous in their methodology. We aimed to develop and validate a classification system to identify Barrett’s neoplasia using AAC. Methods Three expert AAC endoscopists (PB, GLW, OP) formed a working group to identify AAC component criteria of non-dysplastic and dysplastic Barrett’s using a modified Delphi Method. Following this, a panel of 7 AAC experienced endoscopists assessed the performance of each individual criterion by reviewing a bespoke online database of 40 images and 40 videos of non-dysplastic and dysplastic Barrett’s lesions. Finally, we assessed the diagnostic reproducibility of the validated criteria by asking 13 non-AAC experienced endoscopists to complete an assessment tool of 40 images and 20 videos. Results The component criteria identified by the expert AAC endoscopists were as follows Early focal loss of acetowhitening Present : Indicates the presence of neoplasia Absent: Indicates the absence of neoplasia Surface pattern Normal (Large uniformly distributed pits) : Indicates non-neoplastic Barrett’s Abnormal (Compact, irregular or absent pits) : Indicates neoplastic Barrett’s A total of 560 observations were undertaken to validate these criteria. The sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) are shown in Table 1: When the AAC validated criteria are applied by the 13 endoscopists, the sensitivity, specificity, NPV and PPV of detecting neoplastic Barrett’s are 98.5%, 64.0%, 97.5% and 72.5% respectively. Conclusion We have developed and established the validity of a simple classification system to identify Barrett’s neoplasia using AAC. When non-AAC experienced endoscopists apply these criteria, the sensitivity and NPV meet the recommended PIVI threshold. Disclosure of Interest None Declared