Indications for Endoscopic Resection of Early Gastric Cancer

The number of cases with technically unresectable early gastric cancer has been decreasing owing to technological advances in endoscopic submucosal dissection. Conventionally, indications for therapeutic endoscopy were determined based on pathological review of clinical cases of surgery accompanied by lymph node dissection. The gastric cancer treatment guidelines issued by the Japanese Gastric Cancer Association defines absolute indications for endoscopic treatment; however, lesions that are not applicable to absolute indication in the guidelines but have a low risk of lymph node metastasis are treated by endoscopic submucosal dissection in daily clinical practice. A recent prospective multicenter study conducted to verify the safety of expanding indications for endoscopic treatment has shown favorable outcomes, suggesting that the findings will be reflected in the guidelines. Also, with the accumulation of more scientific evidence, indications for endoscopic treatment are expected to expand further in the future. Diagnosis of tumor invasion depth, tumor boarder, and tumor differentiation is a prerequisite for treatment, but specific knowledge and technical know-how are needed to make each diagnosis. This chapter reviews the lesions that are indications for endoscopic treatment and the diagnostic procedures required to determine the indications.