Subsquamous intestinal metaplasia is common in treatment-naive Barrett's esophagus

Background and Aims: Barrett's intestinal metaplasia may extend beneath normal squamous epithelium at the squamocolumnar junction (SCJ) and therefore escape surveillance biopsy sampling. The prevalence of subsquamous intestinal metaplasia (SSIM) in patients undergoing Barrett's esophagus (BE) surveillance is unknown. Our aim was to examine the prevalence and distribution of SSIM proximal to the SCJ in patients undergoing BE surveillance. Methods: We enrolled consecutive patients with biopsy specimen-proven BE. Biopsy specimens were obtained from the squamous epithelium at 5 mm and 10 mm above the SCJ. The primary outcomes were the proportion of patients with SSIM at each level. We further assessed factors associated with SSIM. Results: We examined 515 squamous epithelial biopsy specimens from 106 BE patients (95% men; mean age, 66 years) with a mean Barrett's length of 3.0 cm. SSIM was present in 39% at 5 mm (95% CI, 29.4-48.6) and 21% (95% CI, 11.7-32.1) at 10 mm proximal to the SCJ. Among all biopsy specimens, 13% (95% CI, 10.6-16.6) contained SSIM: 17% (95% CI, 13-21.6) of biopsy samples at 5 mm and 8% (95% CI, 4.3-12.2) at 10 mm proximal to the SCJ. SSIM was more common in the anterior/right lateral position compared with the posterior/left lateral position (21% vs 11%, P = .001). None of the biopsy specimens showed dysplasia. Length of BE or duration of reflux symptoms were not associated with the presence of SSIM. Conclusions: This cross-sectional study found a surprisingly high proportion of SSIM in treatment-naive patients proximal to the SCJ. These findings raise questions regarding BE management and the prevalence of SSIM in normal-appearing esophagus.