Endoscopic therapy for early gastric cancers - from EMR to ESD, from guideline criteria to expanded criteria.

In the late 1990s the development of endoscopic submucosal dissection (ESD) using different knives revolutionized the spectrum of endoscopic resection techniques allowing en bloc resections regardless of the lesion’s size [5] . In combination with new data on the risk of lymph node metastases in early gastric cancer resection, criteria could be extended [6, 7] . The so-called expanded criteria include mucosal cancers without ulceration regardless of the lesion’s size, ulcerated mucosal cancers with a size restriction of 30 mm, and cancers with minute submucosal invasion of ! 500 m (also with a size restriction of 30 mm). Lesions with undifferentiated histology and lymphatic or vascular invasion are still excluded [7, 8] . In 2006 Oka et al. [9] confirmed the presumed advantages of the ESD method in comparison to EMR. ESD showed a significant improvement in en bloc resections and complete resections. For lesions without ulceration, the superiority of ESD was significant even for small lesions of