The feasibility and effect of intraperitoneal administration of regorafenib on peritoneal carcinomatosis from colorectal cancer in the rat.

Aim: Our goal was to investigate the potential use and efficacy of regorafenib for IPEC in an animal model of colorectal derived peritoneal metastases. Twenty four male rats were included. Carcinogenesis was induced in all rats through intraperitoneal injection of cancer.

Material And Methods: Cells at T0. At T1(Day 28) they were randomly allocated 1:1:1:1 into 4 groups and underwent median laparotomy and the corresponding intervention. Specifically, Group A: no other intervention; Group B: cytoreductive surgery; Group C: intraperitoneal chemotherapy with regorafenib; and Group D: cytoreductive surgery and intraperitoneal chemotherapy with regorafenib. At T2 (Day 56) rats were euthanized and laparotomy was performed for further investigation. The primary outcome was the experimental Peritoneal Cancer Index (ePCI) at T2. Secondary outcomes include relative change of body weight between T1 and T2, weight of the ascites, anastomotic leak/peritonitis and death.

Results: The ePCI was significantly lower in Group D as opposed to all other groups. Comparing Group C versus Group A we found a trend towards lesser tumor progression, but no significant difference. Growth of rats in Group D was significantly least affected compared to all other groups. Animals undergoing CRS in Group B developed less ascites than Group A and C. Less ascites was found in Group D compared to Group A and C.

Conclusions: Intraperitoneal chemotherapy with regorafenib combined with cytoreductive surgery may impair metastases' progression.

Key Words: Regorafenib, Chemotherapy, Cytoreductive surgery, Colorectal cancer, Intraperitoneal injection.