This is a multicenter, randomized, controlled, open-label study including patients with localized and locally advanced diffuse and mixed type adenocarcinoma of the stomach and Type II/III GEJ scheduled to receive perioperative chemotherapy combined with intraoperative HIPEC procedure.~The scope of the trial is to evaluate the efficacy as well as the safety and tolerability of the combination of perioperative chemotherapy combined with an intraoperative HIPEC for resectable diffuse and mixed type gastric and GEJ (types II/III) adenocarcinoma. Intraoperative hyperthermic chemoperfusion is summarized under the abbreviation HIPEC in the following.~Patients with localized and locally advanced diffuse or mixed type adenocarcinoma of the stomach and Type II/III GEJ (i.e. ≥cT3 any N or any T N-positive) with exclusion of distant metastases and after receiving neoadjuvant FLOT- therapy will be included in this trial after a central review.~All enrolled patients will have received 3-6 pre-operative cycles (de-escalation or dose modification allowed) of biweekly FLOT (Docetaxel 50 mg/m² in 250 ml NaCl 0.9%, iv over 1 h; Oxaliplatin 85 mg/m² in 500 ml G5%, iv over 2h; Leucovorin 200 mg/m² in 250 ml NaCl 0.9%, iv over 30 min; 5-FU 2600 mg/m², iv over 24 h, q2wk) in the preoperative treatment phase.~After completion of neoadjuvant FLOT- therapy followed by pre-operative tumor assessment, (also including diagnostic laparoscopy prior to start of FLOT), patients without disease progression (expected to be approximately 90% of the patients) will be included into the trial, stratified by initial clinical stage (N- vs. N+), histological type of tumor (Lauren classification diffuse vs. mixed) and study site.~Patients will be randomized 1:1 to receive either postoperative FLOT (Arm A) or postoperative FLOT + intraoperative HIPEC (Arm B).~Arm A (FLOT) Surgery in Arm A is planned to occur 4 to 6 weeks after d1 of last FLOT. Surgery is carried out in kind of gastrectomy, transhiatal extended gastrectomy. Following surgery, patients will receive four further 2-week treatment cycles FLOT in the post-operative treatment phase. Post-operative treatment should start 6 to 8 weeks, but at maximum 12 weeks after surgery.~Arm B (FLOT/ HIPEC) Surgery in Arm B is planned to occur 4 to 6 weeks after d1 of last FLOT. Surgery is carried out in kind of gastrectomy, transhiatal extended gastrectomy. Surgery will be combined with an intraoperative Hyperthermic IntraPEritoneal Chemoperfusion (HIPEC) including cisplatin solution administered at a temperature of 42°C for 90 minutes. Following surgery, patients will receive four further 2-week treatment cycles FLOT in the post-operative treatment phase. Post-operative treatment should start 6 to 8 weeks, but at maximum 12 weeks after surgery.~In both of the arms, tumor assessments (CT or MRI) are performed before randomization prior to surgery, and then every 3 months (radiological tumor assessment) thereafter until progression/relapse, death or end of follow-up. A change from CT into MRI in the follow up period is possible at any time.~During treatment, clinical visits (blood cell counts, detection of toxicity) occur prior to every treatment dose. Safety of FLOT/ HIPEC will be monitored continuously by careful monitoring of all adverse events (AEs) and serious adverse events (SAEs) reported.~The phase III design starts with a safety run-in phase. After 20 patients had curatively intended resection in Arm B, an interim safety analysis is performed that shows feasibility, safety, and tolerability of Arm B planned at the time 8 weeks after the 20th patient in Arm B had curatively intended resection. It is not planned to discontinue recruitment for the interim safety analysis.
This is a multicenter, randomized, controlled, open-label study evaluating efficacy and safety of perioperative FLOT chemotherapy plus intraoperative HIPEC versus FLOT chemotherapy alone in patients with resectable localized and locally advanced diffuse and mixed type adenocarcinoma of the stomach and Type II/III GEJ.