Hepatic tumor spread of colorectal cancer in a laparoscopic animal model

Abstract

Background: We devised a standardized animal model to study the impact of laparoscopic colorectal surgery on intrahepatic tumor cell growth.

Methods: The technique of laparoscopic surgery in the rat was extended by endoscopic inoculation of colon cancer cells (CC531) into the portal vein (1 × 10⁴, 5 × 10⁴, 1 × 10⁵, 3 × 10⁵, 5 × 10⁵ cells/ml) of WAG/Rij rats (n= 25). As controls, five animals underwent laparotomy and open intraportal inoculation of 5 × 10⁴ cells/ml.

Results: Hepatic tumor growth occurred after inoculation of 5 × 10⁴, 1 × 10⁵, 3 × 10⁵, and 5 × 10⁵ cells/ml. Extrahepatic tumor and conflating hepatic tumor was observed after the inoculation of 1 × 10⁵, 3 × 10⁵, and 5 × 10⁵ cells/ml. Concentrations of 5 × 10⁴ cells/ml injected either laparoscopically or via an open technique led to single hepatic tumor nodules. No tumor growth was seen after inoculation of 1 × 10⁴ cells/ml.

Conclusions: Laparoscopic intraportal tumor cell inoculation is a feasible technique to create hepatic metastases. The inoculation of 5 × 10⁴ CC531 cells leads to reliable cell growth that can be used to investigate the impact of various laparoscopic techniques on tumor spread.