Multimodal approach for treatment of peritoneal surface malignancies in a tumour-bearing rat model.

PURPOSE: Surgical cytoreduction of peritoneal surface malignancy of colorectal origin in combination with hyperthermic intraoperative peritoneal chemotherapy (HIPEC) has become an established treatment approach. Only a few of animal models for scientific research on various therapeutic strategies have been described yet. The feasibility of an established rat model with a peritoneal surface malignancy from colorectal origin for treatment investigation should be examined in this study.
METHODS: Peritoneal surface malignancy of colonic origin was induced in 90 male BD IX rats. Animals were randomised into six groups (15 animals per one control and five treatment groups). One treatment group underwent only surgical debulking. The animals of the other four treatment groups received additional interventions: hyperthermic intraperitoneal chemotherapy with mitomycin or gemcitabine, photodynamic therapy or taurolidine lavage. Twenty-one days after treatment, the intraperitoneal status was investigated. Tumour weight, count of tumour nodules and experimental Peritoneal Carcinosis Index (ePCI) were detected.
RESULTS: Extended surgical cytoreduction and additional treatments including HIPEC were feasible in this rat model. All treatment groups had a significant lower tumour weight, account of tumour nodes and ePCI if compared with the control group. Comparing the additional therapies only HIPEC with mitomycin lead to relevant tumour reduction after surgery.
CONCLUSION: This rat model is suitable for research on the multimodal treatment of peritoneal malignancies. A persisting cytoreductive effect of surgical tumour debulking could be proven. Only additional HIPEC therapy with mitomycin showed a significant tumour reduction. This animal model provides the opportunity to investigate different therapeutic strategies.