Comparison of 0.4% Hyaluronic Acid Solution Versus Hydroxyethylamide Solution in Submucosal Endoscopic Resections

1. Design of the study: This is a randomized clinical trial in a single center. The lesions will be randomized into three blocks based on the diameter of the largest axis (less than 3 cm, between 3 - 5 cm and greater than 5 cm). 2. Selection of patients: The population studied will be patients with early esophageal neoplasia diagnosed and/or referred for submucosal endoscopic dissection at the São Paulo Cancer Institute (ICESP), University of São Paulo. 3. Evaluation of effectiveness and definitions: Effectiveness will be measured from the degree of usefulness. The degree of utility will be determined from two variables: obtaining or not a complete block resection and additional number of submucosal injections performed during endoscopic dissection. The solution that results in a complete block resection with a number of additional injections of 0 (excellent utility degree) or 1 (good utility degree) will be considered effective.