Dynamic Contrast Enhanced HCC SABR Liver Study

Inclusion Criteria: All the following criteria must be met: 1. Age \> 18 years old 2. Multi-phase CT scan and/or MRI of the liver within 8 weeks of radiation planning demonstrating: * Liver tumours \< 5 cm * No more than 2 discrete liver tumours * Normal liver \> 700 cc 3. Patients must have HCC diagnosed by either: i) pathological confirmation, or ii) intrahepatic vascular enhancement of the lesion demonstrated by at least two imaging modalities, or iii) intrahepatic vascular enhancement of the lesion demonstrated by one imaging modality if AFP \> 200 in the setting of liver cirrhosis or chronic hepatitis B without cirrhosis (EASL consensus guidelines \[2\]) 4. Liver HCC must be deemed unresectable as determined by an experienced hepatobiliary surgeon, or the patient must be medically inoperable or refuse surgery, 5. Patients must be discussed in a multidisciplinary setting, with representatives from Medical Oncology, Radiation Oncology, Surgery, Interventional Radiology, and Hepatology. Patients must be considered ineligible for standard local treatments, including surgery, liver transplantation, radiofrequency ablation, and targeted biologics. Some subjects could be potential candidates for sorafenib but normally this treatment is not considered before all local treatment options have been considered, as the response rate to sorafenib is low (2% in the SHARP study). Patients might be candidates for sorafenib after progression on the study treatment or if they do not want to participate and in both cases they will be referred to a medical oncologist. Patients may have received prior TACE and had an incomplete response. Ineffective or incomplete TACE is defined as incomplete filling by lipiodol-doxorubicin mixture used by either angiography or CT ≥1 month after TACE or by increasing alpha-fetoprotein level. Patients must have recovered from the effects of previous therapies before SBRT with a minimum 4-week period between TACE and SBRT. 6. Eastern Clinical Oncology Group performance status 0, 1, or 2 (Appendix III), or a Karnofsky performance status of ≥ 60 (Appendix IV) 7. Adequate organ function as assessed by the following blood work: * Hemoglobin ≥ 90 g/L * Absolute neutrophil count ≥ 1.0 bil/L * Platelets ≥ 50 bil/L * AST and ALT not to exceed 3x upper limit of normal 8. Child-Turcotte-Pugh assessment within 8 weeks of treatment date (Appendix II): * Bilirubin ≤ 3 mg/dL (\< 50 µmol/L) * Albumin above 28 g/L * INR \< 1.7 and/or correctable with vitamin K (unless on anticoagulation therapy) * No ascites or encephalopathy * Child-Turcotte-Pugh score must be ≤ 7 9. BCLC Stage B or C (portal venous invasion or liver hilum nodal disease only; (Appendix I) 10. Life expectancy \> 6 months 11. No chemotherapy or systemic therapy concurrent with radiotherapy 12. Previous treatment(s) with radiofrequency ablation, surgery, TACE, Y90, percutaneous ethanol injection, or chemotherapy are not exclusion criteria provided that recurrence or lack of tumour response has been documented. Patients who decline, or not eligible for, these treatments will also be considered eligible. 13. Patient signs a study-specific informed consent form. If the patient's mental status precludes this, written informed consent may be given by the patient's legal representative. A translator will be provided if the patient has a language barrier. 14. Treatment plans meet acceptable dose constraints and Liver Veff is ≤ 0.55 Exclusion Criteria: 1. Patients with active hepatitis, encephalopathy, or ascites related to liver failure 2. Female patients who are pregnant (verify with blood test if patient is pre-menopausal). Pre-menopausal patients may also not become pregnant during participation in this study. 3. Prior external beam radiation to the upper abdomen 4. Patients with distant metastases or extrahepatic nodal progression (patients with portal venous thrombosis and liver hilum nodal involvement remain eligible) 5. Patients who have \< 700 cc of normal liver. 6. Child-Turcotte-Pugh scores \> 7 7. BCLC Stage A, C (N1 and/or M1), D 8. Prior gastric, duodenal, or variceal bleed within the past 2 months