Cytoreductive Surgery (CRS) With/Without HIPEC in Gastric Cancer With Peritoneal Carcinomatosis

Inclusion Criteria: * Histological proved diagnosis of peritoneal metastasized gastric cancer including carcinoma of the AEG No evidence of other distant metastases than peritoneal carcinomatosis with exception of Krukenberg Tumors * Peritoneal Staging with laparoscopy (or explorative laparotomy) and estimation of Peritoneal Cancer Index (PCI) with the possibility of 80% tumor reduction at cytoreductive surgery * Karnofsky Index 70% or better * Written informed consent is obtained prior to commencement of trial treatment Exclusion Criteria: * Other than peritoneal metastasis of the gastric cancer incl. AEG and Krukenberg tumors * Previous or concurrent malignancies, with the exception of adequately treated basal cell carcinoma of the skin or in situ carcinoma of the cervix * Any previous chemotherapy or radiotherapy, and any investigational treatment for gastric cancer * Active systemic infections * Patients with known interstitial lung disease with New York Heart Association classification \> 2 * Serious cardiac dysrhythmia or condition, New York Heart Association classification of III or IV, congestive cardiac failure * cardiac arrhythmia * Uncontrolled hypertension (diastolic blood pressure constantly \>100 mm Hg, systolic blood pressure constantly \> 180 mm Hg). * Inadequate bone marrow function at the beginning of the trial, defined as platelet count less than \<150 GPT/L or neutrophil granulocyte count less than \<1.5 GPT/L * cardiac function EF \< 55% * Inadequate renal function at the beginning of the trial, defined as GFR less than \<60 ml/min * Inadequate liver function at the beginning of the trial, defined as Bilirubin \>1.5 times ULN * Active vaccination within 6 weeks prior to randomisation * Active hepatitis B or C infection * Female patients who are pregnant or breast feeding * Fertile female patients (defined as women with less than a 12-month elapse after the last menstruation) not using an acceptable form of contraception during the trial * Missing of capacity to contract * contraindication to the drugs which are used in the trial * Participation in another therapeutic clinical trial * Persons institutionalised due to regulatory actions ore by court order.