Sa1896 Subsquamous Intestinal Metaplasia and Neoplasia After Radiofrequency Ablation for Barrett's Esophagus: A Systematic Review and Meta-Analysis

Early Cancer) in patients with BE. Methods: We performed a meta-analysis of all primary studies which compared AAC-based diagnosis (index test) with histopathology as the gold standard. The data were extracted both on a "per patient" and "per area" and "per procedure" basis wherever available. Results: Thirteen studies met the inclusion criteria. For diagnosis EN, the pooled sensitivity and specificity for all included studies were 0.92 (95% CI 0.830.97) and 0.96 (95% CI 0.85-0.99), respectively. The positive and negative likelihood ratios (LR's) were 24.97 (95% CI 5.92-105.3) and 0.08 (95% CI 0.04-0.18) respectively. No statistically significant different results were obtained considering only studies with a perpatient analysis. For the characterization of SIM, the pooled sensitivity and specificity for all the included studies were 0.96 (95% CI 0.83-0.99) and 0.67 (95% CI 0.51-0.79) respectively. The positive and negative LR's were 2.9 (95% CI 1.9-4.4) and 0.06 (95% CI 0.02-0.28) respectively. Conclusion: AAC has a high diagnostic accuracy for diagnosing early neoplasia in patients with BO. AAC has high sensitivity but poor specificity for characterizing SIM, suggesting that histological confirmation is necessary when AAC is positive. Sa1896 Subsquamous Intestinal Metaplasia and Neoplasia After Radiofrequency Ablation for Barrett's Esophagus: A Systematic Review and Meta-Analysis Bashar J. Qumseya, Amira Qumseya, Paul A. Bain, Herbert C. Wolfsen Introduction: Radiofrequency ablation (RFA) is widely used for treatment of Barrett's Esophagus (BE) with dysplasia. Subsquamous intestinal metaplasia (SSIM), also referred to as buried Barrett's, has been reported in a minority of patients after RFA. SSIM could lead to the development of buried neoplasia which can be harder to detect. Aim: To conduct a systematic review and meta-analysis assessing the prevalence of SSIM among patients with BE who are treated with RFA. Methods: This study was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Search was performed by the study team with the assistance of an expert librarian using Medline, Embase, Web of Science, and Cochrane Central databases . The last day of search was 11/1/2014. The metameter (estimate) of interest was the prevalence of SSIM in patients with BE who have undergone RFA. Forest plots were used to assess effect size in each of the studies and to show pooled prevalence of SSIM. Random effect models were used when tests of heterogeneity were significant (I2 >50% or p <0.1 for Q statistic). Funnel plots with the trim-and fill method were used to screen for publication bias. The classic fail-safe test was used to investigate the number unpublished studies that would be required to negate disproof our results. Duplicate data was screened for and removed from the final analysis. SSIM was detected on biopsies. Results: Of 1536 articles screened, 29 articles met the inclusion criteria. There were a total of 22 research papers and 7 meeting abstracts totaling 7148 patients in aggregate. There was significant heterogeneity between studies (Cochran's Q 84, p<0.0001 and I2 = 68%). Random effects model showed that the pooled prevalence of SSIM in patients with BE treated with RFA was 3.2% [95% CI 2.1% - 5%], p<0.0001 (Figure 1). Only 4 patients were found to have buried neoplasia. None of the studies had an overdue influence on the pooled prevalence of SSIM. Based on the Classic fail-safe test, we need another 5853 unpublished "null" studies for the p-value in our main analysis to exceed 0.05. Conclusion: In patients with BE treated with RFA, SSIM is detected in a minority of cases. Newer technology, such as optical coherence tomography, may potentially be able to detect more cases of SSIM, thus challenging the findings based on the current the standard of care (biopsies). Future studies should report the prevalence of SSIM before RFA in order to determine the use of RFA is associated with an increased risk of developing SSIM.

(* nodule, ulcer, stenosis) Table 2. Multivariate analysis

Sa1894 Enhanced Characterization of Barrett's Esophagus Islands Through a Revision of the Prague Criteria Rajveer Hundal, Pam Blakely, Clarence K. Wong Background: Barrett's esophagus (BE) is a premalignant condition that can progress to adenocarcinoma of the esophagus and gastroesophageal junction. The Prague C and M criteria was established to provide guidelines on the endoscopic characterization of BE through grading of continuous metaplastic extension from the top of the gastric folds. However, we have observed BE patients with metaplastic columnar ‘islands' that would not be classified under the current criteria. The possibility of dysplasia within these islands and the potential for missed lesions during surveillance or through ablative therapy highlights the need for a revision of the Prague criteria. Aim: To identify and characterize Barrett's esophagus patients that develop metaplastic columnar islands and to assess the utility of a descriptive tool used in addition to the Prague criteria Methods: This retrospective review analyzed consecutive patients with BE referred for management of suspected dysplasia. All patients were assessed with endoscopes equipped with high definition white light, and narrow band imaging. All cases were classified using the Prague criteria for BE at a baseline, mapping upper endoscopy with 4 quadrant biopsies taken at 1 cm intervals from the gastroesophageal junction. After the "C" and "M" of the Prague scale were recorded, all additional islands of metaplastic columnar mucosa were mapped. An "I" designation was given to the most proximal island measured from the gastroesophageal junction. The Barrett's segment was represented as a CxMxIx where "x" is the number in cm from the gastroesophageal junction. Biopsied tissue was assessed for dysplasia, which was confirmed by an expert GI pathologist. Patients with and without islands were compared. Results: From June 2012 to October 2014, 73 patients (mean age 66.0, 61 male, 12 female) were referred for assessment of potential dysplastic BE. 49 (67%) patients did not have any observed islands (mean age 67.4, range 19-87). 25 (33%) patients (mean age 63.6, range 37-84) had islands of Barrett's tissue; 11 with de novo islands and 14 with islands appearing after endoscopic ablation was administered. In the non-island BE group, the mean and range of C and M were 3.3 (011) and 4.8 (1-12) respectively. In the BE group with islands, the mean and range of C, M and I were 2.5 (0-11), 3.5 (0-10) and 5.2(1-10) respectively. 2 patients in the island BE group had biopsy confirmed intramucosal carcinoma. All patients had regular surveillance with or without ablative therapy. Conclusion: The Prague criteria is well validated for endoscopic description of BE. However, we have observed that many patients assessed for BE have island configurations of Barrett's tissue that fall outside of classic Prague descriptors. The potential risk of missed dysplastic lesions warrants the need for a revision to the Prague Criteria.

Sa1897 Predictors of Progression to High Grade Dysplasia and Esophageal Adenocarcinoma During Barrett's Esophagus Endoscopic Surveillance Mariana Omodeo, Lisandro Pereyra, Daniela La Salvia, Claudia M. Godoy, Pablo Luna, Estanislao J. Gómez, Raquel González, José M. Mella, Carolina Fischer, Guillermo N. Panigadi, Daniel G. Cimmino, Silvia C. Pedreira, Luis A. Boerr Background: The likelihood of developing esophageal adenocarcinoma (EAC) in patients with Barrett esophagus (BE) is low. Identifying risk factors for BE progression may allow for a more rational surveillance strategy, stratifying patients according to their individual risk Aim: To identify risk factors for progression to high grade dysplasia (HGD) or EAC in patients with BE undergoing endoscopic surveillance. Methods: A single center observational retrospective study was performed. Patients with BE were retrieved from the medical records of a teaching hospital in a ten year period (January 2004-October 2014). Patients who were endoscopically followed for at least one year were included. Clinical and demographic data (age, gender, personal and familial history of BE, EAC or other neoplasia, body mass index, smoking status) and BE's endoscopic characteristics (length of hiatal hernia, length of the BE segment and the presence of nodularity or visible endoscopic lesions in this segment) were assessed. Chi Square test was used to compare categorical variables. Cox regression analysis was performed to estimate the risk for dysplasia or adenocarcinoma development (composite outcome). Risk was expressed in odds ratio (OR) and its corresponding confidence intervals 95% (CI). A p value ≤ 0.05 was considered statistically significant. Results: A total

Sa1895 The Accuracy of Acetic Acid Chromoendoscopy for the Diagnosis of Specialized Intestinal Metaplasia (SIM) and Early Neoplasia (EN) in Patients With Barrett's Esophagus. Systematic Review and Meta-Analysis Marina C. Coletta, Sarmed S. Sami, Krish Ragunath, Mirella Fraquelli, giovanni casazza, Arun Nachiappan Introduction and Aims: Barrett's Esophagus (BE) surveillance with a random biopsy protocol has many limitations. It is time consuming, invasive, and can lead to sampling error. Chromoendoscopy with acetic acid (AAC) and targeted biopsies has been proposed as an effective alternative to address these limitations. The aim of this study was to assess the diagnostic accuracy of AAC for the detection of SIM and EN (High Grade Dysplasia and

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AGA Abstracts

AGA Abstracts

Table 1. Clinical and endoscopic characteristics of patients with BE without dysplasia and dysplasia / cancer