Randomized controlled phase III trial to investigate superiority of robot-assisted gastrectomy over laparoscopic gastrectomy for clinical stage T1-2N0-2 gastric cancer patients: Japan Clinical Oncology Group study JCOG1907 (MONA LISA study).

TPS254 Background: Postoperative complications reportedly affect oncological outcomes in various cancers according to the timing of adjuvant chemotherapy and by influencing the immune function. Particularly, postoperative intra-abdominal infectious complications, including intra-abdominal abscess, pancreatic fistula, and anastomotic leakage, have been identified as prognostic factors for gastric cancer. Given the negative impact of such complications on patient survival, considering the short- and long-term outcomes, it is important to develop surgical procedures with fewer complications. In Japan, laparoscopic gastrectomy is a standard treatment modality for early gastric cancer. Randomized controlled trials have shown that laparoscopic gastrectomy is relatively less invasive and has similar postoperative complications and non-inferior patient survival rates when compared with open gastrectomy. However, several challenges associated with the procedure need to be overcome, such as the limited movement of the forceps. Robot-assisted gastrectomy allows surgeons to perform more meticulous surgical interventions with articulated devices; therefore, reducing the possibility of postoperative complications, as demonstrated by a few prospective studies performed in Japan. However, a non-randomized controlled trial conducted in Korea reported that there were no benefits of robot-assisted gastrectomy in terms of postoperative complications. Furthermore, no randomized controlled trials have directly compared robot-assisted and laparoscopic gastrectomy to provide solid evidence regarding the merits of the former. Methods: To confirm the superiority of robot-assisted gastrectomy over laparoscopic gastrectomy for patients with cT1-2N0-2M0 gastric cancer, we designed JCOG1907 (UMIN000039825) as a multicenter randomized phase III trial. In the standard arm, we performed laparoscopic gastrectomy with lymphadenectomy, while in the experimental arm, we performed robot-assisted gastrectomy with lymphadenectomy. The primary endpoint is the incidence of postoperative intra-abdominal infectious complications of Clavien–Dindo classification grade ≥II. Major secondary endpoints are relapse-free survival, overall survival, overall postoperative complications, and short-term clinical outcomes after gastrectomy. The planned sample size is 1040 participants, with a one-sided alpha of 5% and a power of 70%, with an expected 3% decrease in postoperative intra-abdominal infectious complications (6% vs. 3%). Over the period of 5 years, patients will be enrolled from 35 Japanese institutions. Enrollment has started in March 2020, and as of August 2020, 30 patients have already been enrolled. Clinical trial information: UMIN000039825.