Patients will remain off chemotherapy after their final microspheres treatment for a minimum of three weeks. Second line treatment options include FDA approved anti-neoplastic agents used in colorectal cancer metastatic to the liver with the exception of bevacizumab and capecitabine, which has been less rigorously studied with relation to Yttrium-90 radioactive microspheres and therefore will not be used. When patients are found to have progressive disease while receiving second line chemotherapy, they will then undergo a comprehensive clinical, laboratory, and imaging assessment and enter the follow-up phase in which they are assessed every five to seven months until death or withdrawal of consent.