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

Abstract

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). Forty-one HCC patients with TVT underwent SIB-PBT using three dose-fractionation schemes: if gross tumour volume <1cm (n=27), 1-1.9cm (n=7), and ⩾2cm (n=7) from gastrointestinal structures, 50GyE (EQD2, 62.5GyE₁₀), 60Gy (EQD2, 80GyE₁₀), 66Gy (EQD2, 91.3GyE₁₀), respectively, in 10 fractions was prescribed to planning target volume 1 (PTV1), and 30GyE (EQD2, 32.5GyE₁₀) in 10 fractions was prescribed to PTV2. Overall, treatment was well tolerated, with no grade toxicity ⩾3. Median overall survival (OS) was 34.4months 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 ⩾80GyE₁₀ 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 <80GyE₁₀. Multivariate analysis showed that TVT response and Child Pugh classification were independent prognostic factors for OS. SIB-PBT is feasible and promising for HCC patients with TVT.