Proton beam therapy for hepatocellular carcinoma associated with inferior vena cava tumor thrombus

Purpose Hepatocellular carcinoma (HCC) with inferior vena cava tumor thrombus (IVCTT) is rare and regarded as an advanced disease stage with poor prognosis. Treatment effect data regarding HCC with IVCTT is scarce and clear evidence has not been established. This study, therefore, aims to examine the safety and effectiveness of proton beam therapy (PBT) for HCC patients with IVCTT. Methods From January 2005 to December 2014, a total of 21 HCC patients with IVCTT were analyzed. The total irradiation doses ranged from 50 to 74 (median 72.6) gray relative biological effectiveness. Results The follow-up period was 4–120 (median 21) months. Regarding acute toxicities, dermatitis of grade 1–2 was observed in all patients, while no grade 3 or higher late toxicity events were encountered. The overall survival (OS) rates for all patients were 62%, 33%, and 19% at 1, 2, and 3 years, respectively. No local recurrences for the treated lesions, including IVCTT, were observed. According to univariate analysis, IVCTT extension type was not associated with prognosis, but only tumor number significantly affected the OS rate ( p = 0.003). For 10 single lesion patients, the longest survival time was 120 months with OS rates of 82%, 64%, and 36% at 1, 2, and 3 years, respectively. Conclusion PBT is safe and effective for HCC patients with IVCTT, especially those with single lesion status. PBT is an important treatment option for HCC patients with IVCTT.