Risk-adapted simultaneous integrated boost-proton beam therapy (SIB-PBT) for advanced hepatocellular carcinoma with tumour vascular thrombosis

Purpose: To evaluate clinical effectiveness and safety of simultaneous integrated boost-proton beam therapy (SIB-PBT) in hepatocellular carcinoma (HCC) patients with tumour vascular thrombosis (TVT). Material and methods: Forty-one HCC patients with TVT underwent SIB-PBT using three dose fractionation schemes: if gross tumour volume <1 cm (n = 27), 1-1.9 cm (n = 7), and >= 2 cm (n = 7) from gastrointestinal structures, 50 GyE (EQD2, 62.5 GyE(10)), 60 Gy (EQD2, 80 GyE(10)), 66 Gy (EQD2, 91.3 GyE(10)), respectively, in 10 fractions was prescribed to planning target volume 1 (PTV1), and 30 GyE (EQD2, 32.5 GyE(10)) in 10 fractions was prescribed to PTV2. Results: Overall, treatment was well tolerated, with no grade toxicity >= 3. Median overall survival (OS) was 34.4 months and 2-year local progression-free survival (LPFS), relapse free survival (RFS), and OS rates were 88.1%, 25%, and 51.1%, respectively. Patients treated with EQD2 of >= 80 GyE(10) tended to show better TVT response (92.8% vs. 55.5%, p = 0.002) 2-year LPFS (92.9% vs. 82.5%, p = 0.463), RFS (28.8% vs. 19%, p = 0.545), and OS (58.4% vs. 46.8%, p = 0.428) rates than those with EQD2 of <80 GyE(10). Multivariate analysis showed that TVT response and Child Pugh classification were independent prognostic factors for OS. Conclusions: SIB-PBT is feasible and promising for HCC patients with TVT. (C) 2016 Elsevier Ireland Ltd. All rights reserved.