This study is a randomized, multi-center study that will compare the efficacy and safety of selective internal radiation therapy (SIRT) using SIR-Spheres microspheres plus a standard chemotherapy regimen of FOLFOX6m versus FOLFOX6m alone as first-line therapy in patients with non-resectable liver metastases from primary colorectal carcinoma.

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 Investigator.

Inclusion Criteria:

• Age 18 years or older
• Willing and able to provide written informed consent
• 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)
• All imaging evidence used as part of the screening process must be within 28 days
• Suitable for either treatment regimen
• WHO performance status 0-1
• Adequate hematological, renal and hepatic function
• Life expectancy of at least 3 months without any active treatment

Exclusion Criteria:

• Evidence of ascites, cirrhosis, portal hypertension, main portal or venous involvement or thrombosis as determined by clinical or radiologic assessment
• Previous radiotherapy delivered to the liver
• Non-malignant disease that would render the patient unsuitable for treatment according to the protocol
• Peripheral neuropathy > grade 2 (NCI-CTC)
• Dose-limiting toxicity associated with previous adjuvant 5-FU or oxaliplatin chemotherapy
• Prior non-adjuvant chemotherapy for any malignancy. Adjuvant chemotherapy for colorectal cancer is permitted provided that it was completed more than 6 months before entry into the study
• Pregnant or breast feeding
• Concurrent or prior history of cancer other than adequately treated non-melanoma skin cancer or carcinoma in situ of the cervix
• Allergy to contrast media that would preclude angiography of the hepatic arteries