Long-term outcome of a randomized phase III trial exploring the significance of extensive intraoperative peritoneal lavage in addition to standard treatment for ≥ T3 resectable gastric cancer: CCOG 1102.

1Background: Extensive intraoperative peritoneal lavage (EIPL) for gastric cancer reportedly improved survival by physically removing and reducing intraperitoneal-free cancer cells in a small-scale randomized trial (Ann Surg 2009). To confirm this, we conducted a multicenter randomized Phase III trial. Methods: Eligibility criteria: (i) histologically confirmed primary gastric adenocarcinoma, (ii) clinically T3(SS), T4a(SE) or T4b(SI), (iii) clinically M0, and (iv) scheduled for total or distal gastrectomy. Patients were intraoperatively randomized to either the EIPL group or the non-EIPL group after confirming the ≥T3 status and resectability. In the EIPL group, peritoneal lavage was conducted at least 10 times using 1L of saline before the closure of the abdomen. In the non-EIPL group, the lavage was conducted with ≤3L of saline. The primary end-point was disease-free survival (DFS). To detect the difference of 15% in 3-year DFS with a both-sided alpha of 5% and 80% power, the planned sample size was 30...