Primary outcomes of a phase II trial of laparoscopic/robotic total gastrectomy with spleen-preserving splenic hilar dissection for locally advanced proximal gastric cancer involving the greater curvature (JCOG1809).

BACKGROUND: Advanced proximal gastric cancer (APGC) involving the greater curvature (Gre) sometimes metastasized to the splenic hilar lymph node (No.10 LN), so total gastrectomy with splenectomy has been the standard treatment aiming for complete removal of it; however, the high incidence of complications has been problematic. METHODS: We conducted a multicenter phase-II trial to assess the safety and efficacy of laparoscopic or robotic spleen preserving splenic hilar dissection (LR-SHD) which has the potential to reduce complications. Eligibility criteria included cT2-4a resectable APGC involving the Gre without obvious No.10 metastasis. Macroscopic type 4 and large type 3 (≥ 8 cm) were excluded. LR-SHD with total gastrectomy (D2+No.10) was performed by qualified surgeons. The primary endpoint was the proportion of postoperative pancreatic fistula and/or intra-abdominal abscess (Grade ≥ III). The sample size was 85 considering a threshold of 16% and one-sided alpha of 0.1. RESULTS: Between August 2019 and December 2024, 85 eligible patients (cT2/T3/T4a = 32/38/15) were enrolled, and resection was performed in 81. The median operation time was 379 min, and the median blood loss was 30 ml. No.10 metastasis was observed in 12.5% (10/80). Overall complications (Grade ≥ III) occurred in 9.9% (8/81). Pancreatic fistula and/or intra-abdominal abscess occurred in 1.2% (1/81; 80% confidence interval: 0.1-4.7%), which was significantly lower than prespecified threshold (one-sided p < 0.0001). No treatment-related mortality occurred. CONCLUSIONS: This study confirmed the safety and feasibility of LR-SHD when performed by experienced surgeons. This procedure is highly promising for treating APGC with the Gre invasion.