Peritoneal Cancer Index to Evaluate Efficacy in a Peritoneal Cancer Model

Peritoneal carcinomatosis (PC) represents an extreme form of metastatic cancer progression, commonly occurring in gastric, ovarian and colorectal cancers. Metastatic tumor models leading to PC help better understand the toxicities, timing and efficacy of novel therapies to improve survival in patients affected by PC. However, the development of such models can be challenging, stressing the importance of working with validated models with known tumour growth kinetics and/or response to standard of care (SOC) treatments. InnoSer’s oncology team has extensive experience and frequently carries out validation studies of novel and/or customized models on request.  

Here, we present a case study showcasing an explorative study to validate a model for peritoneal carcinomatosis of colorectal origin in rats. The development of peritoneal cancer was induced using the CC-531 rat colon adenocarcinoma cell line using pre-determined seeding density in Wag-Rij rats. The cells were injected intraperitoneally, which induced the dissemination of intraperitoneal lesions representing peritoneal metastases of colorectal cancer (CRC).

Inoculation of colorectal carcinoma cells leads to the development of intraperitoneal tumor lesions representing peritoneal carcinomatosis of CRC. (A) Tumour burden was expressed as peritoneal cancer index (PCI), based on the size and number of nodules (macroscopic inspection and presence of intra-abdominal lesions) in 11 pre-specified inspection sites. (B) PCI was determined on days 7, 14, 21 and when humane endpoint (HEP) was reached via an autopsy. Data is represented as mean ± SEM.  

All efficacy studies can be complemented with histopathology readouts with in-house expert pathologist evaluation. The H&E-stained image below shows a liver metastasis of a colorectal carcinoma in a patient-derived xenograft (PDX) model.