Current Understanding of Ablative Radiation Therapy in Hepatocellular Carcinoma

Ashwathy S Mathew,1 Laura A Dawson2,3 1Department of Radiation Oncology, Apollo Proton Cancer Centre, Chennai, Tamil Nadu, India; 2Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada; 3Department of Radiation Oncology, University of Toronto, Toronto, Ontario, CanadaCorrespondence: Laura A DawsonRadiation Medicine Program, Princess Margaret Cancer Centre, 610 University Avenue, Toronto, Ontario, M5G 2M9, CanadaTel +1-416-946-6513Fax +1-416-946-6566Email Laura.Dawson@rmp.uhn.caAbstract: The role of ablative stereotactic body radiotherapy (SBRT) in hepatocellular carcinoma (HCC) has been evolving over the last few decades. SBRT has mostly been used in early stages of HCC, including few (≤ 3 in number) tumors, small tumours (< 3 cm in size), as well as larger tumours which are ineligible for other ablative modalities, mostly without vascular invasion. In early stage HCC, SBRT is used as a definitive treatment with curative intent or with intent to bridge to liver transplant. Retrospective and prospective institutional series document a high rate of local control (68– 95% at 3 years) following SBRT. This coupled with a low risk of toxicity makes this non-invasive ablative treatment an attractive option for patients who are ineligible for other ablative treatments. Small randomized studies of ablative radiation have also shown non-inferiority of radiation as compared to radiofrequency ablation (RFA). Currently, SBRT is widely available as a safe and effective liver directed therapy, although there is a need for more studies providing higher level evidence. This review gives a brief overview of SBRT and the evidence for its use in HCC patients with ablative intent.Keywords: hepatocellular carcinoma, radiotherapy, stereotactic body radiotherapy, SBRT, stereotactic ablative radiotherapy, SAB