Endoscopic mucosal resection (EMR) has become the standard of care for removal of large flat and sessile neoplastic lesions of the GI tract. Recently, endoscopic submucosal dissection (ESD) was introduced in Japan as an alternative technique, which allows en bloc resection of large lesions. The applications of EMR and ESD are expanding and many Western endoscopists are adopting these techniques. Paris classification and Kudo pit pattern classification allows prediction of the depth of invasion of early neoplastic lesions and thus, avoids resection of lesions invading the deep submucosa which have higher rates of lymphatic spread. ESD of early stomach cancer is the standard of care in Japan. Recent published reports from Western countries showed comparable results for ESD of early gastric cancers to those done in Japan. Recently, EMR combined with ablation has been used frequently in Western countries for treatment of high-grade dysplasia in early adenocarcinoma of the esophagus. Although ESD of early neoplastic lesions of the esophagus is technically difficult, few promising reports were published proving the feasibility of this technique in the West. ESD has been shown to achieve higher en bloc resection and lower rates of tumour recurrence in removal of lateral spreading colonic polyps. A hybrid technique of circumferential submucosal incision followed by en bloc EMR has been used for removal of large colonic lesions in some Western endoscopy centres. In Western countries, training for ESD is challenging given the lack of training in the relatively easier early gastric cancer lesions. Animal model training combined with observing experts in ESD could be an alternative for Western endoscopists. Inspite of obstacles, ESD applications are continuing to grow in Western countries.Le texte complet de cet article est disponible en PDF.