Inclusion Criteria:  Patients 18 years or over Patients with adenocarcinoma-type gastric non-resectable péritonéale carcinomatosis. Patients without metastasis other than peritoneal. WHO performance status <3 Patients treated either with PIPAC administered in alternation with systemic chemotherapy (PIPAC_CHEM) or by systemic chemotherapy alone (ONLY_CHEM) Patient informed  Exclusion Criteria:  - Patients opposed