Multicenter Planning Comparison of Stereotactic Body Radiotherapy for Hepatocellular Carcinoma with Major Portal Vein Tumor Thrombosis (KROG 16-17)

Abstract

Background/Aims: To evaluate the technical feasibility of stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma (HCC) with the major portal vein tumor thrombosis (PVTT). Methods: Ten institutions affiliated with the Korean Stereotactic Radiosurgery Group were provided the contours of four cases: the first case was the first branch PVTT with sufficient normal liver volume (NLV), the second was the first branch PVTT with insufficient NLV, the third was the main trunk PVTT at confluence level, and the fourth was the main trunk PVTT with entire length. The institutions were asked to make SBRT plans according to their current treatment protocols and to complete facility questionnaires. Results: Based on institutional protocols, SBRT was feasible in nine institutions for the first case (32-60 Gy in 3-5 fractions), in eight institutions for the second case (32-50 Gy in 3-5 fractions), in seven institutions for the third case (35-60 Gy in 3-5 fractions), and in four institutions for the fourth case (35-42 Gy in 4-5 fractions). The other institutions recommended hypo- or conventional fractionation due to insufficient NLV or gastrointestinal organ proximity. With analysis of the SBRT dose to the central hepatobiliary tract, the major PVTT could theoretically be associated with a high risk of hepatobiliary toxicity. Conclusions: Although SBRT is a technically feasible option for HCC with the major PVTT, there was a variability among the participating institutions. Therefore, further studies will be necessary to standardize the practice of SBRT for the major PVTT.