Subsquamous Extension of Intestinal Metaplasia Is Detected in 98% of Cases of Neoplastic Barrett's Esophagus

BACKGROUND & AIMS: Subsquamous intestinal metaplasia (SSIM) has been observed after endotherapy in patients with neoplastic Barrett's esophagus (BE). However, it is not clear whether SSIM occurs in untreated patients. Incompletely eradicated SSIM could provide a source of recurrent disease. We assessed its prevalence in a large cohort of patients who had not received endoscopic therapy. METHODS: Two experienced pathologists analyzed 138 samples of 506 resection specimens found to contain squamous epithelium from 110 patients with neoplastic BE treated by widespread endoscopic mucosal resection (92 men; mean age, 66 years). The maximum extent of SSIM was measured. RESULTS: Of the 138 samples analyzed, 124 (89.9%) were found to contain SSIM from 108 of the 110 patients (98.2%). The mean length of SSIM was 3.3 mm (range, 0.2-9.6 mm; 25% >= 5 mm); SSIM length correlated with BE length (P <.05). In 83 of 138 samples (60.1%), the SSIM consisted partially or entirely of neoplasias of different grades, with a mean subsquamous extension of 3.3 mm; the extension correlated with grade of neoplasia (P =.0001). CONCLUSIONS: Most patients with BE with neoplasia (of all grades) have subsquamous extension of intestinal metaplasia, including subsquamous extension of lesions at the squamocolumnar junction. Therefore, biopsy and resection of neoplastic BE should extend at least 1 cm into the squamous epithelium.