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