Standardized CRS-HIPEC Procedure Protocol

The institutions performed the CRS–HIPEC procedure under the same standardized protocol. Extensive debulking with peritonectomy and, when needed, multiorgan resections were performed, as described by Sugarbaker et al.10 (link),11 (link) and all the latter recommendations. The purpose of the cytoreduction was to obtain a macroscopically complete CRS (R1) resection, which means that no macroscopically visible residual tumor was left at the end of the surgical resection. After the cytoreduction, the open perfusion protocol of the abdominal cavity with mitomycin C was performed.17 (link) The inflow temperature of the perfusate was 41–42 °C. As soon as this temperature was reached, mitomycin C was added, 35 mg/m² body surface, in three fractions (one half, one fourth, and one fourth of the total dose) with a 30-min interval. Mitomycin C was used under the same schedule for all first HIPEC procedures. If a patient had undergone a HIPEC before, procedures were done with intraperitoneal oxaliplatin (460 mg/m²), systemic folinic acid (20 mg/m²), and 5-fluorouracil (5-FU; 400 mg/m²). When new institutions started performing CRS–HIPEC, a surgeon of an experienced institute monitored the procedure to ensure that the procedure was performed according to the Dutch HIPEC protocol.