Stereotactic body radiotherapy (SBRT) is an emerging non-invasive treatment modality for treatment of hepatocellular carcinoma (HCC) when curative treatments cannot be applied. It allows ablative doses to be delivered safely to the focal HCC, sparing uninvolved liver. Recent prospective trials have demonstrated a 1 year local control rate of 87% with SBRT 1. We present our tertiary liver transplant unit experience of SBRT with CyberKnife M6 for treatment of HCC when other established treatment modalities were considered unsuitable.

Retrospective review of records including multidisciplinary meetings, laboratory data and imaging studies of all patients who underwent SBRT with CyberKnife for HCC between August 2014 and June 2017 was conducted. Radiological diagnosis of HCC was made using contrast enhanced CT or MRI 2. All patients were discussed at multi-disciplinary meetings and were referred for Cyberknife if they were not suitable for other established treatment modalities. A total of 24 patients received HCC SBRT with follow up data available for 21 patients. Follow up data for...

Complete response (CR) to treatment was seen in 10/21 patients (48%). 8/21 (38%) patients achieved partial response (PR). Figure (2) Out of patients with CR, 5 initially had PR to treatment but had CR at subsequent MRI scans. 2 patients had an increase in size of treated liver lesions but subsequent 3 and 6 monthly MRI scans showed PR to treatment. 1 patient had stable disease. Follow up data for 2 patients were not availableas 1 patient proceeded on to successful liver transplant post SBRT...

We were able to achieve partial to complete response with short follow-up in 18/21 (86%) patients in our cohort with minimal treatment toxicity. Longer duration of follow up with imaging is required to assess full response of treatment with SBRT. The optimum follow up interval and response criteria to SBRT requires further investigation. CyberKnife SBRT is an effective treatment in patients with HCC not suitable for standard treatment.

We would like to acknowledge the contribution of Mrs Eva Arneric, Senior Clinical Trial Coordinator of SCGH Radiation Oncology Clinical Trials and Research Unit for collating our patients' data and her assistance in this study.

Bujold A, Massey CA et al. Sequential Phase and II trials of steretotactic body radiotherapy for locally advanced hepatocellular carcinoma. J Clin Oncol 2013; 31:1631-1639 European Association for the Study of the Liver and European Organisation for Research and Treatment of Cancer. EASL–EORTC Clinical Practice Guidelines: Management of hepatocellular carcinoma. J Hepatol 2012; 56(4):908-943. Lencioni R, Llovet J. Modified RECIST (mRECIST) assessment for hepatocellular carcinoma. Seminars in liver disease. 2010;30 (1):52-60.