Systemic Antitumor Treatment with or Without Pressurized Intraperitoneal Aerosol Chemotherapy for Colon Peritoneal Metastases (PIPOX02)

Inclusion Criteria: * ECOG performance status of 0 to 2; * Histopathologically confirmed colonic adenocarcinoma with synchronous or metachronous peritoneal metastasis (PM); * Unresectable PM defined as any of the following: * PCI \>15 * Extended small bowell involvement * Poor general condition contra-indication to a major abdominal surgery (eg: a complete cytoreductive surgery), as decided by the medico-surgical team of the investigator's site specialised in peritoneal carcinomatosis in charge of the patient. * A surgical exploration performed less than 4 weeks before inclusion (if not, a laparoscopic exploration must be performed); * First line systemic chemotherapy for advanced / metastatic colonic adenocarcinoma. Systemic chemotherapy in an adjuvant setting is allowed if completed more than 6 months before recurrence and without persistent oxaliplatin-induced neuropathy; * No extended intraperitoneal adherences defined by at least 9 out of 13 abdominal regions correctly explored during surgical exploration (laparoscopy or laparotomy; Exclusion Criteria: * Other cancer treated within the last 3 years, with the exception of in situ cervical carcinoma or basocellular carcinoma; * Rectal cancer primary (tumor \<15 cm from the anal verge); * Mutational status corresponding to microsatellite instability high (MSI-H) or mismatch repair deficient (dMMR); * Complete or partial bowel obstruction unresponsive to medical treatment; * Extraperitoneal polymetastatic diseases. (Only oligometastatic1 diseases are allowed for inclusion); * History of abdominal fistula, gastrointestinal perforation, intra-abdominal abscess within 6 months prior to enrolment; * Active gastrointestinal bleeding; * Inflammatory bowel disease; * Peripheral neuropathy according to the Common Toxicity Criteria for Adverse Events (CTCAE) version 5.0, grade ≥2