Barretts mucosa is a premalignant condition of the oesophagus, which can progress to cancer. Oesophageal cancer is aggressive, with a 5 year survival of only ~15%. High risk Barretts mucosa, containing high grade dysplasia or early cancer, can be removed by endoscopic mucosal resection (EMR) during gastroscopy. If patients can be effectively treated by EMR while they have premalignant or early malignant disease, it is a curative procedure.