Barrett's esophagus detection: Multiple biopsies are useful, even better if you have an \u201cX\u201d on your map

Barrett\u2019s esophagus (BE), defined as the replacement of physiological squamous epithelium of the lower esophagus by metaplastic columnar epithelium containing goblet cells, is a premalignant condition that can lead to esophageal adenocarcinoma through dysplasia with an annual risk of about 0.5%. The major determinant of BE is represented by gastro-esophageal reflux, which promotes chronic inflammation and progressively induces the metaplastic transformation in predisposed subjects. Indeed, several pathophysiological studies carried out with the state-of-the-art technology clearly demonstrated that the severity of BE directly correlates with esophageal acid exposure and reflux occurrence of any type. Futher, BE and GERD share multiple common risk factors, including obesity and smoke. Long-term cancer survival may be improved with early detection of BE with intestinal metaplasia and subsequent appropriate stratification of the precursor lesions into the categories of no dysplasia, low-grade dysplasia (LGD), and high-grade dysplasia (HGD). Accordingly, endoscopic surveillance reduces the risk of mortality from esophageal adenocarcinoma and is recommended in patients with BE. In the last decade, several new imaging modalities, such as chromoendoscopy or narrow-band imaging, have increased significantly the diagnostic yield of endoscopic surveillance, however, their use is not yet recommended for routine use because of limited reproducibility, poor availability of advanced diagnostic equipment, increased costs and prolonged procedure-related inspection time. Thus, endoscopic examination with accurate identification, description and location of Barrett\u2019s segments and subsequent adequate biopsies collection represent the essential steps for Barrett\u2019s detection and adequate quality of surveillance. In this issue of the Journal, Bibb\uf2 and coworkers, report a retrospective review of their prospectively maintained database of patients with histologically proven non-circumferential BE, and analyse whether BE and associated dysplasia have a preferred location within the esophageal circumference. To our knowledge, this is the first study investigating and reporting the preferred location of BE lesions in a population of Western patients and one of the few describing a spatial predilection of advanced lesions (high-grade dysplasia or intraepithelial carcinoma) within the esophageal circumference. Among 443 patients with endoscopic appearance of BE, the Authors further analysed a total of 192 subjects (male=143/female=49) with non-circumferential BE histologically confirmed by two expert histopathologists (excellent inter-observer agreement with a K of 0.90) according to international guidelines (10,11) and documented by endoscopic pictures and/or videos. Multiple lesions were diagnosed in 110 (57%) of them, for a total amount of 352 metaplastic areas: 323 (91.8%) simple metaplastic lesions without dysplasia (S-BEs), 28 (7.9%) lesions associated with dysplasia (D-BEs), and one (0.3%) lesion with adenocarcinoma. Barrett\u2019s esophagus lesions without dysplasia were more frequently and significantly located in the posterior wall of the esophagus (38.4%), rather than in the right wall (28.8%), the anterior wall (22.6%), or the left wall (10.2%). Similarly, dysplastic BE lesions were significantly more common in the posterior wall (39.3%) than in the anterior wall (35.8%), the right wall (21.4%) or the left wall (3.5%), respectively. Thus, the right hemi-circumference was the preferred location of BE and advenced lesions within the esophageal circumference, as previously shown in similar studies on smaller cohorts of patients from both Eastern and Western Countries. Moreover, several potential explanations for these findings have been proposed, including the intrinsic pressure asymmetry of the lower esophageal sphincter and the importance of overweight/obesity for GER occurrence during recumbent position (22,23); however, a clear mechanistic evaluation has not been done and it will be likely object of future research on this topic. In conclusion, these data are relevant because they can represent a guide for gastroenterologists during the endoscopic assessment of BE and to address biopsies on the areas with an increased probability to find metaplastic lesions. In particular, since the detection of lesions in BE is directly related to the time spent to inspect the columnar-lined segment, as described by Gupta et al (24), these findings support that the attention should be focused at the right hemisphere of the esophagus where advanced lesions occur with considerably higher frequency. Therefore, high-quality endoscopy for BE detection and surveillance may be done despite the lack of an advanced diagnostic equipment and without excessively prolonging the inspection time, provided that multiple biopsies are done and remembering that, sometimes, the pathophysiological nature of gastro-esophageal reflux may help us positioning an \u201cX\u201d on the right hemi-circumference of the esophagus