Safety of intraperitoneal Mitomycin C versus intraperitoneal oxaliplatin in patients with peritoneal carcinomatosis of colorectal cancer undergoing cytoreductive surgery and HIPEC.

BACKGROUND: Colorectal peritoneal carcinomatosis (PC) is commonly treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). There is an ongoing international debate about which intraperitoneal chemotherapeutic agent is preferred, Mitomycin C (MMC) or oxaliplatin. We questioned whether the type of chemotherapeutic agent influenced postoperative complication rates or short-term survival. METHODS: In this retrospective cohort study patients with colorectal PC who underwent CRS-HIPEC between January 2010 and December 2016 were included. Until March 2014 patients had preferentially been treated with MMC and thereafter with oxaliplatin in an iso-osmotic glucose/electrolyte dialysis (Dianeal®) carrier solution. Main outcomes were postoperative complications, disease free survival (DFS) and overall survival (OS). Survival analyses and multivariable analyses were performed. RESULTS: One hundred four patients received MMC and 73 patients oxaliplatin. Postoperative complications did not differ between groups (44.2% (MMC) versus 43.8% (oxaliplatin); P = 0.958). Median DFS was 12.5 months (IQR 6.4-32.4) in the MMC-group and 13.1 months (IQR 6.1-NA) in the oxaliplatin-group (P = 0.669). Median OS was 37.2 months (IQR 17.2-NA) in the MMC-group and 29.4 months (IQR 17.0-NA) in the oxaliplatin-group (P = 0.764). The type of chemotherapeutic agent did not influence OS in multivariable analysis (oxaliplatin versus MMC HR 1.09 (95%CI 0.58-2.06)). The HIPEC-phase was shorter for oxaliplatin (median 32 (IQR 31-34) versus 91 min (IQR 90-92) for MMC (P < 0.001)). CONCLUSION: Intraperitoneal oxaliplatin reduced the chemoperfusion time when compared to intraperitoneal MMC without adversely influencing complication rates or short-term survival. It may therefore be the preferential drug in CRS-HIPEC procedures for colorectal PC.