Inclusion Criteria:  Provision of written informed consent prior to any study specific procedures. ECOG Performance Status Score 0,1 or 2 Adequate kidney, liver, bone marrow function according to laboratory tests For females of childbearing potential, a negative pregnancy test must be documented ≥ 18 years old and <75 years old Colorectal cancer with peritoneal metastases All patients deemed eligible for CRS and HIPEC according to clinical routine management during a HIPEC multidisciplinary board at each respective hospital can be included.  Exclusion Criteria:  Previous severe toxicity/allergic reactions to systemic chemotherapy agents oxaliplatin or irinotecan or 5-fluorouracil Unable to tolerate intensified HIPEC treatment due to comorbidity Metastasis other than peritoneum Pregnant or lactating (nursing) women Active infections requiring antibiotics Active liver disease with positive serology for active hepatitis B, C, or known HIV Concurrent administration of any cancer therapy other than planned study treatment within 4 weeks prior to and up to 4 weeks after study treatment Incomplete cytoreduction defined as completeness of cytoreduction score 1-3 Histopathology of other origin than colorectal cancer