Endoscopic diagnosis and treatment of early cancer in the alimentary tract.

Due to the recent widespread use of detailed endoscopy together with careful scrutiny of the mucosa using dye-spraying techniques, there has been a general acceptance in Japan that early malignancies in the alimentary tract may not appear polypoid or ulcerative. Regardless of organ, superficial early cancers have been reported. These lesions appear as faint mucosal irregularities or discolorations, which may be difficult to distinguish from nonspecific inflammation or trauma. The recognition of these malignancies has prompted the development of new techniques for their treatment. Endoscopic mucosal resection (EMR) which can resect lesions as completely as specimens removed at open surgery, has become the first choice of treatment for early digestive cancer. The lesions that can be removed by EMR should be those which hardly ever carry lymph node metastases. Endoscopically, they are shown to be flat esophageal cancers, gastritis-like cancers and colorectal cancers less than 2 cm in flat elevated type or less than 1 cm in depressed type. In spite of the advances in characterizing early cancers and an emerging consensus on indications and contraindications for EMR, much work remains to be done. New techniques will continue to push the limits of what can be achieved via an endoscope.