["The optimal management of high-grade dysplasia in Barrett's esophagus remains controversial. A biopsy protocol consisting of 4 quadrant jumbo biopsies (every 1 cm) with biopsies of mucosal abnormalities (the Seattle protocol) is considered to be the optimal method for detecting early cancers in patients with high-grade dysplasia, although it has never been validated. This study aimed to determine the frequency of unsuspected carcinoma at esophagectomy in Barrett's esophagus patients with high-grade dysplasia who underwent the Seattle protocol and to compare the findings with those of a less rigorous biopsy protocol.", 'Thirty-three patients with high-grade dysplasia underwent esophagectomy. None had obvious mass lesions at preoperative endoscopy. Patients were divided into group 1 (preoperative surveillance biopsies according to Seattle protocol) and group 2 (4 quadrant biopsies every 2 cm). Preoperative and postoperative diagnoses were confirmed by 2 expert gastrointestinal pathologists.', 'Unsuspected intramucosal cancer was found in 8 of 20 (40%) patients in group 1 versus 4 of 13 (30%) in group 2 (P = .6). Preoperative mucosal nodularity was observed in 4 of 8 (50%) postoperative intramucosal cancers from group 1 versus 3 of 4 (75%) from group 2. Multifocal high-grade dysplasia was seen preoperatively in 7 of 8 (87.5%) postoperative intramucosal cancers in group 1 versus 2 of 4 (50%) in group 2. No patient had submucosal cancer or lymph node metastases at surgery.'] Does the Seattle protocol more reliably predict the detection of cancer at the time of esophagectomy than a less intensive surveillance protocol?