Comparing Hepatic Intra-arterial Injection of Yttrium-90 Microspheres Versus Fluorouracil (5FU) in Colorectal Cancer Metastatic to the Liver Only

Inclusion Criteria: * Histologically proven colorectal adenocarcinoma, metastatic to the liver only. * Failure of prior chemotherapy for advanced colorectal cancer. * Adequate laboratory values of hematologic, renal and liver function * World Health Organization (WHO) performance status (PS) \<= 2 * Written consent Exclusion Criteria: * Pregnant or lactating patients * Other tumor type than adenocarcinoma (leiomyosarcoma; lymphoma). * Patients with cirrhosis or other chronic liver disease * Thrombosis of the hepatic main artery of the portal vein * Lung shunting \> 20% as determined by nuclear medicine breakthrough scan * Patients with serum bilirubin \> 1.0 x upper limit of normal (ULN) or with AST and/or ALT and/or alkaline phosphatase \> 5 x ULN * Patients with concurrent or within 4 week period administration of any other experimental drugs. * Other serious illness or medical conditions.