This study is a randomized multi-center trial that will assess the effect of adding Selective Internal Radiation Therapy (SIRT), using SIR-Spheres microspheres®, to a standard chemotherapy regimen of FOLFOX as first line therapy in patients with non-resectable liver metastases from primary colorectal adenocarcinoma.

Treatment with the biologic agent bevacizumab, if part of the standard of care at participating institutions, is allowed within this study at the discretion of the treating Investigator.

Inclusion Criteria:

• Unequivocal and measurable CT evidence of liver metastases which are not treatable by surgical resection or local ablation.
• Limited extra-hepatic metastases in the lung and/or lymph nodes are permitted (Lung: 5 lesions total, < 1 cm, or 1 single lesion of up to 1.7 cm; Lymph nodules in one single anatomic area (pelvis, abdomen or chest): any number, < 2 cm).
• Suitable for either treatment regimen.
• Prior chemotherapy for metastatic colorectal cancer is not allowed.
• WHO performance status 0-1.
• Adequate hematological, renal and hepatic function.
• Age 18 years or older.
• Willing and able to provide written informed consent.
• Life expectancy of at least 3 months without any active treatment.

Exclusion Criteria

• Evidence of ascites, cirrhosis, portal hypertension, main portal or venous tumor involvement or thrombosis as determined by clinical or radiologic assessment.
• Previous radiotherapy delivered to the upper abdomen.
• Non-malignant disease that would render the patient unsuitable for treatment according to the protocol.
• Peripheral neuropathy > grade 1 (NCI-CTC).
• Dose limiting toxicity with previous adjuvant 5-FU or oxaliplatin chemotherapy.
• Prior non-adjuvant chemotherapy for any malignancy. Adjuvant chemotherapy for colorectal cancer is not an exclusion criteria provided that it was completed more than 6 months before entry into the study.
• Pregnant or breast-feeding.
• Other active malignancy.