PIPAC for Peritoneal Metastases of Colorectal Cancer

Eligible patients are adults who have: * a World Health Organisation (WHO) performance status of ≤1; * histological or cytological proof of PM of a colorectal or appendiceal carcinoma; * unresectable disease determined by abdominal computed tomography (CT) and a diagnostic laparoscopy or laparotomy; * adequate organ functions (haemoglobin ≥5.0 mmol/L, neutrophils ≥1.5 x 109/L, platelets ≥100 x 109/L, serum creatinine \<1.5 x ULN, creatinine clearance ≥30 ml/min, and liver transaminases \<5 x ULN); * no symptoms of gastrointestinal obstruction; * no radiological evidence of systemic metastases; * no contraindications for oxaliplatin or 5-fluorouracil/leucovorin; * no contraindications for a laparoscopy; * no previous PIPAC-procedures. Enrolled patients are excluded from the analyses in case they did not receive a first ePIPAC-OX, e.g.: * due to systemic metastases on baseline thoracoabdominal CT, or; * due to non-access during first ePIPAC-OX, or; * due to resectable disease during first ePIPAC-OX. Importantly, enrolment is allowed for patients with an unresected primary tumour (if asymptomatic) and for patients in various lines of palliative treatment, including patients who refuse, have not had, or do not qualify for first-line palliative systemic therapy. All potentially eligible patients are discussed by a multidisciplinary team. Enrolled patients are informed about the potential consequences of postponing or discontinuing standard palliative treatment by a medical onc…