Effectiveness and safety of proton beam therapy for advanced hepatocellular carcinoma with portal vein tumor thrombosis

To evaluate the clinical effectiveness and safety of proton beam therapy (PBT) in advanced hepatocellular carcinoma (HCC) patients with portal vein tumor thrombosis (PVTT). Twenty-seven HCC patients with PVTT underwent PBT, including 22 patients with modified International Union Against Cancer (mUICC) stage IVA,five patients with stage IVB primary tumors, and 16 with main PVTT. A median dose of 55 GyE (range, 50-66 GyE) in 20-22 fractions was delivered to a target volume encompassing both the PVTT and primary tumor. Overall, treatment was well tolerated, with no toxicity of grade ≥ 3. Median overall survival (OS) times in all patients and in stage IVA patients were 13.2 months and 16 months, respectively. Assessments of PVTT response showed complete response in 0 of 27 (0 %) patients, partial response in 15 (55.6 %), stable disease in 10 (37 %), and progressive disease in 2 (7.4 %) patients, with an objective response rate of 55.6 %. PVTT responders showed significantly higher actuarial 1-year local progression-free survival (LPFS; 85.6 % vs. 51.3 %), relapse-free survival (RFS; 20 % vs. 0 %) and OS (80 % vs. 25 %) rates than nonresponders (p < 0.05 each). Multivariate analysis showed that PVTT response and mUICC stage were independent prognostic factors for OS. Our data suggest that PBT could improve LPFS, RFS, and OS in advanced HCC patients with PVTT and it is feasible and safe for these patients. (orig.)