Effectiveness and feasibility of external beam radiotherapy for hepatocellular carcinoma with inferior vena cava and/or right atrium involvement: a multicenter trial in Korea (KROG 17-10).

Purpose: Hepatocellular carcinoma (HCC) involving the inferior vena cava (IVC) and/or right atrium (RA) can affect systemic circulation, causing fatal complications. Standard treatment is yet to be established due to its rarity and intractability. We sought to determine the clinical efficacy of external beam radiotherapy (EBRT) in HCC treatment.Patients and methods: Our group designed this multicenter trial and recruited patients with HCC and IVC and/or RA involvement. Forty-nine patients from six institutions received EBRT with median dose of 46.7 (range: 35.4-71.5) Gy during 2009-2016. The primary outcome was overall survival (OS), and relevant predictors were evaluated.Results: Median follow-up length was 9.3 (range: 1.1-119) months. Median survival, 1-, and 2- year OS rates were 10.1 months (95% confidence interval [CI]: 7.5-12.7 months), 43.5%, and 30.1%, respectively. Significant factors affecting OS were alpha-fetoprotein level ≥300 ng/mL (risk ratio [RR]: 2.34, p = .025), tumor multiplicity (RR: 2.56, p = .028), and patient volume of institutions (high- vs. middle volume centers) (RR: 3.58, p = .001). Local control rates were 88.7% and 74.5% at 1 and 2 years, respectively. The most common first failure site was the lung (21/49, 42.9%) followed by liver outside the EBRT field (17/49, 34.7%). One case of possible radiation-induced liver disease was noted, with transient alkaline phosphatase elevation.Conclusion: EBRT can yield favorable local control in HCC with IVC and/or RA involvement. Systemic treatment may be more indicated as factors reflecting tumor aggressiveness were significant, and first distant failure is common.