Laparoscopic surgery revolutionized the surgical treatment of gastric cancer saving large incsion and associated pain. Robotic surgical system was introduced to enhance the minimally invasive surgery using articulating robotic arm. The da vinci SP system, which enables single-port surgery, can allow surgeon to provide radical gastrectomy with minimal scar and associated pain.

This study is a phase 1/2, single-arm surgical clinical trial. The primary endpoint is the safety of da vinci robotic gastrectomy. The secondary endpoint is operative time, bleeding, bowel recovery, and hospital stay. In the clinic, informed consent is received from patient who is scheduled to undergo radical gastrectomy. After the general anesthesia, low midline transverse incision is made at suprapubic area. After inserting SP port into the peritoneal cavity, additional port is inserted via right flank that would be used for assistant's energy device and suction devices. Radical subtotal gastrectomy is perfromed using cardiere-forceps, monopolar scissors, and maryland forceps. Reconstruction after gastrectomy is decided according to surgeon's preference. three days after gastrectomy, if the diet build up is complete and the patients has no evidence of complication, the patient is discharged from the hospital. Four weeks after gastrectomy, the patient will be followed up at the clinic. Major complication event within 30days after gastrectomy will be analyzed as primary endpoint as well as other secondary endpoints.

Inclusion Criteria:

• Biopsy confirmed adenocarcinoma of stomach scheduled to undergo radical gastrectomy
• Between 20-80
• ASA score (American society of anesthesiology) class: I - III
• Signed to informed consent after through explanation about the study

Exclusion Criteria:

• distant metastasis
• EMR/ESD canddiate
• complicated gastric cancer (obstruction or perforation)
• Active other primary tumor
• Vulerable subject (illiterate, pregnant)