This retrospective, multinational, single-arm study will be conducted in at least 8 sites. An interim analysis will be conducted with data from 100 patients with up to 10 well defined HCC tumor(s) and with at least one tumor ≥3 cm. Normal tissue absorbed dose using pre-procedural 99mTc MAA SPECT or SPECT/CT imaging will be measured to allow the mean absorbed normal tissue dose corresponding to a ≤15% probability of CTCAE grade 3 or higher hyperbilirubinemia (in the absence of disease progression) to be calculated. Total bilirubin will be recorded and graded according to CTCAE version 4.02. All dose-related SAEs at 3 months follow-up will be followed until resolution, death or lost-to-follow-up. AEs related to disease progression will not be considered related to TheraSphere.

Recently published evidence indicates a correlation between yttrium-90 dose delivered to the tumor and normal tissue with safety and efficacy outcomes but there are no validated methods to consistently measure dose delivered to the tumor and normal tissue. In contrast to the standard clinical approach based on average dose to one target volume, this trial, sponsored by Biocompatibles UK, will explore an alternative two-compartment TheraSphere dosimetry methodology to calculate absorbed dose to tumor and normal tissue

Inclusion Criteria:

• Up to 10 well defined unilobar/bilobar HCC tumor(s) per lobe with at least one tumor ≥3 cm ± PVT
• Liver dominant disease (limited extra-hepatic metastases in the lung and/or lymph nodes are permitted (up to 5 lesions in the lung, with each individual lesion ≤2cm; any number of lymph node lesions with each individual lesion ≤2 cm).
• Child Pugh stage A or B7.
• BCLC A, B or C.
• Must be male or female, 18 years of age or older.
• Bilirubin ≤2 mg/dL.
• Tumor replacement <50% of total liver volume assessed by diagnostic imaging consisting of multi-phase contrast enhanced CT or contrast enhanced MRI.
• Diagnostic imaging consisting of multi-phase contrast enhanced CT or contrast enhanced MRI within 3 months prior to TheraSphere® administration.
• Infusion of 99mTc-MAA in a single arterial location sufficient to cover up to 10 well-defined tumors per lobe ≤ 6 weeks prior to TheraSphere® administration.
• Patients must have received TheraSphere® in a single treatment setting in one or more arterial locations sufficient to cover up to 10 well-defined tumors based on angiography. Subsequent TheraSphere® treatment to the second lobe may occur at least 4 weeks following the initial TheraSphere® treatment.
• For patients receiving a second TheraSphere® treatment bilirubin levels must have been recorded prior to the second treatment
• Patients must have had clinical evaluation (assessment of liver specific AEs) and laboratory evaluation (at least a serum bilirubin level) at baseline.
• Tumor(s), ≥3 cm, measurable by mRECIST and RECIST 1.1 at baseline

Exclusion Criteria:

• Prior external beam radiation treatment to the liver.
• Prior loco-regional liver directed therapy (cTACE, DEB-TACE and SIR-Spheres).
• Prior liver transplantation.
• Whole liver TheraSphere® treatment following prior liver resection.
• TheraSphere administration to ≤2 segments (e.g., radiation segmentectomy).
• Additional active therapy (TACE and treatment with SIR-Spheres) between first TheraSphere treatment and 3 month (90 days) imaging.
• Hepatic vein invasion.
• Diagnosis of disease progression at peri-procedural imaging as compared to the baseline imaging (physician's discretion).

Patients with up to 10 well-defined unilobar HCC tumors per lobe with at least one tumor ≥3 cm ± PVT.