A Multicenter Prospective Cohort Study Comparing Random Biopsies Versus Wide-Area Transepithelial Brush-Sampling (WATS) for Surveillance of Barrett's Esophagus, the WATS-EURO2 Study

Inclusion Criteria: * Patients age: ≥ 18 years * BE with a circumferential extent of ≥2cm and a total maximum extent of ≤18cm (in case of prior ER: BE length is measured after ER). Or a circumferential extent of 0-1 cm with a maximum extent of ≥4cm. * Cohort 1: Patients referred for work-up of IND, LGD, HGD or low-risk cancer (m1 to sm1, without lympho-vascular invasion and poor differentiation), either diagnosed in random biopsies or in prior endoscopic resection specimen within 18 months prior to baseline endoscopy * Cohort 2: Patients with known BE without a diagnosis of dysplasia in the last 18 months, enrolled in endoscopic surveillance programs * Ability to give written, informed consent and understand the responsibilities of participation Exclusion Criteria: * Patients with visible lesions according to the Paris classification at the time of the WATS and random biopsy testing (prior endoscopic resection is allowed) * Patients with high-risk cancer after endoscopic resection: either sm2/3 invasion, poor differentiation, lympho-vascular invasion, or R1 vertical resection margin * Patients within six weeks after endoscopy with biopsies and/or ER * History of esophageal or gastric surgery other than Nissen fundoplication * History of esophageal ablation therapy * Presence of esophageal varices * Subject has a known history of unresolved drug or alcohol dependency that would limit ability to comprehend or follow instructions related to informed consent, post-treatment instructions, or follow-up guidelines