Randomized controlled phase III trial to investigate superiority of robot-assisted gastrectomy over laparoscopic gastrectomy for clinical stage T1-4aN0-3 gastric cancer patients (JCOG1907, MONA LISA study): a study protocol

Background Laparoscopic gastrectomy (LG) is considered a standard treatment for clinical stage I gastric cancer. Nevertheless, LG has some drawbacks, such as motion restriction and difficulties in spatial perception. Robot-assisted gastrectomy (RG) overcomes these drawbacks by using articulated forceps, tremor-filtering capability, and high-resolution three-dimensional imaging, and it is expected to enable more precise and safer procedures than LG for gastric cancer. However, robust evidence based on a large-scale randomized study is lacking. Methods We are performing a randomized controlled phase III study to investigate the superiority of RG over LG for clinical T1-2N0-2 gastric cancer in terms of safety. In total, 1,040 patients are planned to be enrolled from 46 Japanese institutions over 5 years. The primary endpoint is the incidence of postoperative intra-abdominal infectious complications, including anastomotic leakage, pancreatic fistula, and intra-abdominal abscess of Clavien-Dindo (CD) grade [greater than or equal to] II. The secondary endpoints are the incidence of all CD grade [greater than or equal to] II and [greater than or equal to] IIIA postoperative complications, the incidence of CD grade [greater than or equal to] IIIA postoperative intra-abdominal infectious complications, relapse-free survival, overall survival, the proportion of RG completion, the proportion of LG completion, the proportion of conversion to open surgery, the proportion of operation-related death, and short-term surgical outcomes. The Japan Clinical Oncology Group Protocol Review Committee approved this study protocol in January 2020. Approval from the institutional review board was obtained before starting patient enrollment in each institution. Patient enrollment began in March 2020. We revised the protocol to expand the eligibility criteria to T1-4aN0-3 in July 2022 based on the results of randomized trials of LG demonstrating non-inferiority of LG to open surgery for survival outcomes in advanced gastric cancer. Discussion This is the first multicenter randomized controlled trial to confirm the superiority of RG over LG in terms of safety. This study will demonstrate whether RG is superior for gastric cancer. Trial registration The protocol of JCOG1907 was registered in the UMIN Clinical Trials Registry as UMIN000039825 ( Keywords: Stomach neoplasms, Robotic surgery, Minimally invasive surgery, Postoperative complication, Multicenter study, Randomized controlled t