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

摘要

Endoscopic mucosal resection (EMR) has been established in the treatment of early gastric cancers (EGCs) for more than 20 years. In 1984 EMR was first described by Tada et al. [1] as a new technique called strip biopsy. Inoue et al. [2] developed another resection technique in 1993 using a cap-fitted panendoscope to suck targeted lesions into the cap and resect them with a snare (EMR-C). This technique gained worldwide acceptance over the following years and was considered the treatment of choice for EGCs in Japan and also in the Western world. However EMR has technical limitations. En bloc resections are restricted to lesions with a diameter of 20 mm or less, and the endoscopist's view during resection is limited. In 2006 Chiu [3] concluded: 'Conventional EMR is limited by the blindness of the resection and the size of the specimen'. Resulting piecemeal and incomplete resections lead to difficulties in histopathological assessment of R0 resections and to an increased risk of recurrence. In the era of EMR the Japanese guideline criteria for endoscopic resection of EGCs were therefore restricted to elevated lesions of <20 mm in diameter and depressed lesions without ulceration of <10 mm in diameter. Ulcerated lesions and lesions with undifferentiated histology, lymphatic or vascular involvement and submucosal invasion were excluded due to possible lymph node metastases [4].