In spite of recent advances in diagnostic tools such as computed tomography, endoscopic ultrasonography, and positron-emission tomography, preoperative diagnosis of lymph node metastases in patients with upper gastrointestinal (GI) cancer has been problematic because of the low sensitivity and accuracy in the detection of micrometastases. To overcome this issue, the sentinel node (SN) concept has attracted attention in recent years and is anticipated to become a novel diagnostic tool for the identification of clinically undetectable lymph node metastases in patients with early upper GI cancer. For early-stage gastric cancer, in which a better prognosis can generally be achieved using conventional surgical approaches, individualized, minimally invasive gastrectomy based on a combination of laparoscpic surgery with SN navigation surgery should be established as the next surgical milestone. Several issues remain to be resolved in laparoscopic gastrectomy with three-dimensional computed tomography navigation.