Stereotactic Body Radiation Therapy in Treating Patients With Liver Cancer That Cannot Be Removed by Surgery

Inclusion Criteria: * Life expectancy \> 3 months * Eastern Cooperative Oncology Group (ECOG) performance status =\< 2 * HCC diagnosed by either of the following approaches: * Histologic confirmation of HCC on biopsy * Evidence of vascular enhancement of suspected lesion on at least two imaging techniques * Evidence of vascular enhancement on a single technique if the alpha-fetoprotein (AFP) is \> 200 ng/mL in the setting of cirrhosis or chronic hepatitis B/C * HCC must be deemed unresectable by an experienced surgeon or patient must be medically inoperable or extra-hepatic metastases must be present (making resection an inappropriate treatment option) or patient must have declined the option of surgery after consultation with a surgeon * Barcelona Clinic Liver Cancer score of B or C required (i.e., intermediate or advanced stage HCC) * Prior liver resection or ablative therapy is permitted * Prior transarterial chemoembolization (TACE) is permitted * Patients must have recovered from the effects of previous therapy * Maximal tumor size of 15 cm and \> 700 cc of uninvolved liver * Hemoglobin \> 9.0 g/L * Absolute neutrophil count \>= 1.0 bil/L * Platelets \>= 70,000 bil/L * Total bilirubin \< 2 mg/dL * International normalized ratio (INR) =\< 1.5 or correctable with vitamin K (higher INR acceptable if patient is on Coumadin) * Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) =\< 6 times upper range of normal Exclusion Criteria: * Active hepatiti…