Selective portal vein embolization and colorectal liver metastases in rat: a new experimental model for tumor growth study.

BACKGROUND: Portal vein embolization (PVE) has been proposed to induce hypertrophy of liver before major resection. Because there are some concerns about the effect on tumor growth, experimental research is needed, requiring reliable small animal model. The aim was to assess technical feasibility of PVE model in rat and to report colorectal liver metastases (LM) tumor growth. METHODS: LM were induced in 40 rats by injecting DHDK12 cells into the left liver lobe. At d 7, a portography was performed through a laparotomy in 20 rats allowing the left PVE. Twenty rats without PVE served as control. All rats were sacrificed at d 30. Liver and tumor volume were calculated. RESULTS: Mortality rate was 20% (n=8). PVE was successful in 15/19 rats (79%). Compared with control rats, the left PVE induced both significant atrophy of the left lobe (3.5±0.8 versus 7.4±0.9 mm3, P<0.0001) and contralateral hypertrophy (5.8±1.1 versus 3.6±0.7 mm3, P<0.0001). LM tumor volume in the left liver was significantly decreased in PVE group compared to control, 124.4±95.7 mm3versus 231.1±90.1 mm3, P=0.008. CONCLUSION: PVE is feasible in rats with a 79% success rate. Significant hypertrophy of the remnant liver and atrophy of the embolized liver were noted suggesting the efficacy of PVE. LM tumor growth decreased significantly in the embolized lobe. Our model can be used for experimental studies evaluating tumor growth and effects of new drugs against LM in a situation that mimics the human situation before partial hepatectomy.