1.3 Radiation therapy (RT) for the HCC The use of RT in HCC is increased with the radiation technological advances. In the unresectable patients, RT showed 50 to 60% response rate with the dose response relationship. Recently, stereotactic body radiation therapy (SBRT) showed excellent local control and comparable survival rate in thoracic tumor. In the HCC, SBRT also showed 75 to 100% local control rate without significant elevation of the toxicities. One study reported that 24 to 54 Gy SBRT achieved 87% 1year local control and 17 months overall survival. The standard treatment of unresectable HCC is sorafenib, but Korean Liver Cancer Study Group (KLCSG) recommend RT as an option in localized unresectable HCC. Furthermore, Radiation Therapy Oncology Group (RTOG) started randomized trial to confirm the effect of SBRT in unresectable HCC (RTOG 1112).