Endoscopic submucosal dissection (ESD) was developed in Japan, early in this century, to provide a minimally invasive yet curative treatment for the large numbers of patients with early gastric cancer identified by the national screening program. Previously the majority of these patients were treated surgically at substantial cost with the significant risk of short and long-term morbidity. Enbloc excision of these early cancers, most with a limited risk of nodal metastasis, allowed complete staging of the tumor, stratification of the subsequent therapeutic approach and potential cure.