A new reproducible model of hepatic and peritoneal metastases from colonic carcinoma.

A new technique for the generation of tumour nodules in both liver and peritoneal cavity has been developed in Wistar wag rats. The cell line 192 NRc was derived from a 1,2-dimethylhydrazine (DMH)-induced colonic carcinoma and was cultured on positively charged ion-exchange polystyrene microspheres. The tumour grew to confluence on the spheres, adhering firmly by pseudopodial extensions, enabling washing and injections of spheroids without significant dislodgement of cells. 5 x 10(4) tumour spheroids injected into the portal vein produced a mean of 35 +/- 24 (S.D.) nodules in the liver with an average diameter of 1.5 +/- 0.55 (S.D.) mm at 14 days. The spheroids did not enter the hepatic veins and therefore did not produce pulmonary metastases. Similarly, 5 x 10(3) tumour spheroids injected into the peritoneal cavity, after gently abrading the peritoneum with gauze, produced a mean of 65 +/- 37 (S.D.) nodules with an average diameter of 1.6 +/- 0.39 (S.D.) mm at 14 days. The tumour continued to grow as discrete nodules in both locations until near the time of death at approx. 36 days from inoculation. This animal model is reproducible and will allow the study of a number of treatment modalities for discrete neoplastic lesions in both the liver and peritoneal cavity at any stage of tumour growth without interference from tumour at unwanted sites.