DISEASE CHARACTERISTICS: History of carcinoma of the colon or rectum in which the primary site has been completely resected Measurable or evaluable unresectable liver metastases with one or more of the following: Involvement of all 3 major hepatic veins, the portal vein bifurcation, or the retrohepatic vena cava Involvement of the main right or the main left portal vein and the main hepatic vein of the opposite lobe Disease requiring more than a right or left trisegmentectomy Six or more metastatic lesions distributed diffusely in both lobes of the liver