Immunotherapy With Y90-RadioEmbolization for Metastatic Colorectal Cancer

Inclusion Criteria: * Age ≥18 years * Histological or cytological confirmation of colorectal cancer with metastasis to the liver. Mismatch repair or microsatellite instability status of the tumor needs to be known. Tumors need to be mismatch repair proficient (for mismatch repair deficient tumors immunotherapy is already approved). * Patient must have at least 1 liver lesion measurable as defined in the protocol * Must have liver metastases and be appropriate for treatment with Y-90 radioembolization therapy as determined by the treating medical oncologist and interventional radiologist/oncologist, and nuclear medicine physician(s). NOTE: the goal of therapy is safety and parenchymal sparing. Typically, since the treatment is personalized, the goal is to have at least 30% liver parenchymal sparing post treatment. * Must have a metastatic focus amendable to biopsy. It is permissible to use same or alternative lesion for biopsy for assessment for tumor response and changes in microenvironment (mandatory pre- and post-Y90-RE biopsy). * At least 2 but no more than 3 lines of therapy allowed in metastatic setting. These include at least treatment with a fluoropyrimidine, oxaliplatin, and/or irinotecan-based therapy, an anti-VEGF therapy and, if RAS wild-type, an anti-EGFR therapy, unless deemed intolerant or not suitable by the treating oncologist. NOTE: adjuvant and/or maintenance chemotherapy does not count as an additional line of therapy. (Patients with more than 3 lines of t…