Radiotherapy with Targeted Therapy or Immune Checkpoint Inhibitors for Hepatocellular Carcinoma with Hepatic Vein and/or Inferior Vena Cava Tumor Thrombi.

Purpose: This study evaluated the clinical outcomes of patients with hepatocellular carcinoma (HCC) with hepatic vein tumor thrombus (HVTT) and/or inferior vena cava tumor thrombus (IVCTT) receiving radiotherapy (RT) combined with systemic therapies.

Patients and methods: Patients with HCC with HVTT and/or IVCTT who received RT were identified at our institution. The prescription doses were 30-65 Gy for planning target volume and 40-65 Gy for the gross tumor volume. Targeted therapy and immune checkpoint inhibitors were used concurrently if patients were at a high risk of or already had distant metastasis. After RT completion, follow-up was performed at 1, 3, 6, and 12 months, and 3 to 6 months thereafter. The objective response rate (ORR), overall survival (OS), progression-free survival (PFS) and toxicity were recorded.

Results: Thirty-four patients were retrospectively enrolled between January 2016 and September 2021. Most patients received concurrent targeted therapy (70.6%) and/or post-RT (79.4%). The in-field ORR and disease control rates were 79.4% and 97.1%, respectively. The OS rates were 77.6% at 1 year and 36.3% at 2 years (median OS, 15.8 months). The median PFS and median in-field PFS were 4.2 months and not reached, respectively. The PFS and in-field PFS rates were 24.6% and 79.2% at 1 year, 19.7% and 72.0% at 2 years, respectively. An alpha-fetoprotein level >1000 ng/mL was a significant prognostic factor for worse OS (HR, 5.674; 95% CI, 1.588-20.276; p=0.008); in-field complete/partial response was a significant prognostic factor for better OS (HR, 0.116; 95% CI, 0.027-0.499; p=0.004). The most common site of first failure was the lungs (13/34 patients, 38.2%), followed by the liver (7/34 patients, 20.6%). No patients developed radiation-induced liver disease or pulmonary embolism during follow-up.

Conclusion: Combining RT and systemic therapy was safe and effective in treating patients with HCC with HVTT and IVCTT.