Holmium-166 Transarterial Radioembolization in Unresectable, Early Stage Hepatocellular Carcinoma.

Inclusion Criteria: 1. Age ≥ 18 years 2. Multidisciplinary tumor board decision for locoregional treatment 3. Freely given, written informed consent 4. Patients with unresectable HCC with a single nodule ≤ 8 cm or up to three nodules with a diameter of ≤ 5 cm (each) eligible for selective radioembolization (including position changes of infusion catheters) 5. Non-cirrhotic patients or Child-Pugh A cirrhosis 6. ECOG performance status 0-1 7. Using an acceptable method of contraception throughout the study until survival follow up (for subjects of childbearing potential) 8. Adequate hematological, renal and liver function. Adequate hematological function defined as: * Hemoglobin ≥ 6 mmol/L (9.7 g/dL) * WBC ≥ 3.0 x 10E9/L * Absolute neutrophil count ≥ 1.5 x 10E9/L * Platelet count ≥ 50,000/mm3 Adequate renal function defined as: * Serum urea and serum creatinine \< 1.5 times upper limit of normal (ULN) * Creatinine clearance ≥ 45 ml/min Adequate liver function defined as: * Total bilirubin ≤ 35µmol/L (2.05 mg/dL) * Albumin ≥ 30 g/L * AST and ALT ≤ 5X ULN Exclusion Criteria: 1. Diffuse and/or infiltrative HCC (defined as HCC consisting of multiple tiny liver nodules spreading throughout the entire liver or entire lobe, without a dominant nodule) 2. Hypoperfused HCC (defined as a lack of tumor blush (i.e. reduced or no uptake of contrast fluid) observed on the intra-procedural CT) 3. No full, selective arterial coverage on intra-procedural CT 4. Life expectancy \< 6 months 5. Child-Pugh score ≥7 points 6. Prior liver transplantation 7. Prior locoregional or systemic anti-cancer therapy for HCC and previous malignancies 8. Macrovascular invasion (defined as macrovascular invasion of the hepatic and/or portal vein main branches) 9. Extrahepatic metastases 10. Clinically significant ascites 11. Hepatic encephalopathy 12. Untreated active hepatitis B and/or C 13. Work-up imaging showing: * Lung shunt \> 30 Gy is simulated on 166Ho-scout imaging; or * Uncorrectable extrahepatic deposition of simulated 166Ho-scout dose activity. Activity in the falciform ligament, portal lymph nodes and gallbladder is accepted; or * Anticipated ineffective tumor targeting (\< 150 Gy mean tumor simulated absorbed dose) of 166Ho-scout for each lesion; or * Entire tumor burden not within the perfused liver volume (possible extrahepatic collateral supply of the tumor); or * Perfused liver volume \> 50% of whole liver tissue 14. Pregnant or breast-feeding 15. Current or history of cancer other than HCC, except adequately treated non-melanoma skin cancer or carcinoma in situ of the cervix 16. In the Investigator's opinion there is a reason that could limit the patient's ability to participate in the study, compliance with follow-up requirements or impact the scientific integrity of the study 17. Concurrently enrolled in another study, unless it is an observational non-interventional study