Spatial distribution of dysplasia in Barrett's esophagus segments before and after endoscopic ablation therapy: a meta-analysis.

Background: Dysplasia in Barrett’s esophagus is focal and difficult to locate. The aim of this meta-analysis was to understand the spatial distribution of dysplasia in Barrett’s esophagus before and after endoscopic ablation therapy. Methods: A systematic search was performed of multiple databases to July 2019. The location of dysplasia prior to ablation was determined using a clock face orientation (right or left half of the esophagus). The location of dysplasia post-ablation was classified as within the tubular esophagus or at the top of the gastric folds (TGF). Results: Thirteen studies with 2234 patients were identified. Pooled analysis from 6 studies (819 lesions in 802 patients) showed that before ablation, dysplasia was more commonly located in the right half versus the left half (OR 4.3; 95% CI [2.33-7.93]; p<0.01). Pooled analysis from 7 studies showed that dysplasia after ablation recurred in 101/1432 (7.05%; 95% CI [5.7-8.4%]) patients. Recurrence of dysplasia was located more commonly at the TGF (n=68) as compared to the tubular esophagus (n=34) (OR 5.33; 95% CI [1.75-16.21]; p<0.01). Of the esophageal lesions, 90% (27/30) were visible whereas only 46% (23/50) of the recurrent dysplastic lesions at TGF were visible (p<0.01). Conclusion: Before ablation, dysplasia in Barrett’s esophagus is found more frequently in the right half of the esophagus versus the left. Post-ablation recurrence is more commonly found in the top of the gastric folds and is non-visible as compared to the tubular esophagus, which is mainly visible.