Adjuvant HIPEC in High Risk Colon Cancer

Background: The peritoneum is the second most common site of recurrence in patients with colon cancer. Early detection of peritoneal carcinomatosis (PC) by imaging is difficult and adjuvant systemic treatment does not seem to affect peritoneal dissemination in contrast to haematogenous dissemination in the liver or lungs. Of all patients eventually presenting with clinically apparent PC, only a quarter have potentially curable disease. The curative option is cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CR/HIPEC), but the effectiveness depends highly on the extent of disease and is associated with a considerable complication rate. These clinical problems underline the need for effective adjuvant intraperitoneal therapy in high risk colon cancer patients in order to prevent the development of PC with treatment at a subclinical stage. Study design: This will be a multicentre study in which 176 eligible patients will be randomized to adjuvant HIPEC followed by adjuvant systemic chemotherapy in the experimental arm, or the standard adjuvant systemic chemotherapy alone in the control arm. Adjuvant HIPEC will be performed preferably simultaneously or within 10 days after resection of the primary tumour, either by laparoscopy or open approach, similar to the technique used for resection of the primary tumour. If adjuvant HIPEC cannot be performed within 10 days (i.e. complicated postoperative course), the procedure will be delayed until 5 to 8 weeks postoperatively. Subsequently, patients will receive routine adjuvant chemotherapy (CAPOX) within 3 weeks from HIPEC. Diagnostic laparoscopy will be performed routinely after 18 months postoperatively in both arms of the study in patients without evidence of disease based on routine follow-up using CT imaging and CEA. If peritoneal carcinomatosis is found during staging laparoscopy, CR/ HIPEC will be performed in patients with a maximum of 5 involved regions and without evidence of systemic disease. Study population: Patients who underwent intentionally curative resection for a T4N0-2M0 or intra-abdominally perforated colon cancer. Intervention: Adjuvant HIPEC procedure: access to the abdominal cavity by laparoscopy or laparotomy under general anaesthesia, adhesiolysis if necessary, complete staging of the intra-abdominal cavity, positioning of in- and outflow catheters, perfusion with a minimum of 2l isotonic dialysis fluid at a flow rate of 1-2l/min and an inflow temperature of 42-43˚C. Before the beginning of HIPEC, 5-fluorouracil 400 mg/m2 and leucovorin 20 mg/m2 will be administered intravenously to potentiate oxaliplatin activity. Oxaliplatin (460 mg/m2) is added to the perfusate after attaining at least 42 degrees inflow temperature with a total of 30 minutes perfusion time. Outcomes: Primary endpoint is peritoneal recurrence-free survival at 18 months. Secondary endpoints are number of participants with adverse events as a measure of safety and tolerability, incidence of PC at end of follow-up with or without concomitant liver/lung metastases, percentage of false negative CT at 18 months (second look laparoscopy/laparotomy as gold standard), disease-free survival, overall survival, quality of life and costs.