Observational SIR-Spheres Study for the Treatment of Unresectable Liver Tumors (SIRtain Registry)

Inclusion Criteria: * Age 18 years or older * Confirmed diagnosis of: * Unresectable hepatocellular carcinoma (HCC) Or * Unresectable liver metastases from colorectal cancer (mCRC) refractory to or intolerant to chemotherapy * Identified as a candidate for SIR-Spheres treatment as deemed appropriate during the normal course of practice * Planned to receive SIR-Spheres treatment to the liver for the first time * Provision of signed patient informed consent Exclusion Criteria: * Prior radiation treatment to the liver Caveat: Sequential selective internal radiation therapy (SIRT) treatment is allowed * Patients participating in any interventional clinical trial with an investigational product, device, or procedure * Need for surrogate consent. Patients who are not able to consent on behalf of themselves are not eligible.