Safety and Efficacy Study of Ablative Radiation Therapy for Large Liver Metastases Invading Into the Inferior Vena Cava and Heart

PURPOSE Ablative radiation therapy (A-RT) is a noninvasive treatment for primary liver tumors. Tumors that invade the inferior vena cava (IVC) and heart may lead to acute liver failure. We evaluated the safety, toxicities, and outcomes of A-RT in patients with symptomatic IVC invasion and intracardiac metastases. METHODS A retrospective study at Memorial Sloan Kettering Cancer Center (2017-2023) included patients with primary liver cancers invading the IVC and heart treated with A-RT. Clinicopathologic and imaging data were extracted. Adverse events were graded using Common Terminology Criteria for Adverse Events (version 3) V5.0, and tumor response was determined by two independent liver radiologists. Dose-volume histograms were analyzed, and Kaplan-Meier analysis was used to estimate survival and evaluate hepatic and distant progression. RESULTS Eight patients (six hepatocellular carcinoma, two cholangiocarcinoma) with liver tumors (median gross tumor volume [GTV] 394 cc; median GTV/liver ratio, 23%) received A-RT (biologically effective dose >100 Gy) in 10-25 fractions. At treatment, Child-Pugh scores were A5 in three, A6 in three, and B8 in two patients; 50% had progressed on systemic therapy. The median age was 66 years (range, 47-92), with 63% female patients. Excellent dosimetry was achieved (median D95, 99.75%; V100, 94.85%), sparing a median of 923 cc of liver, and the median heart volume receiving 30-40 Gy was 13.5%. Grade 1 fatigue was the most common toxicity (87%), with no grade ≥3 or long-term toxicities. The median overall survival was 16 months (67% at 12 months). CONCLUSION In this study, A-RT for large primary liver tumors with IVC or cardiac invasion did not increase cardiopulmonary events versus historical controls and appeared to prevent tumor progression and life-threatening complications.