Yttrium-90 Selective Internal Radiation Therapy for Right Hepatic Malignancies: A Clinical Outcome Study

Background: Surgical resection offers long-term survival for liver malignancies, but insufficient future liver remnant (FLR) volume often precludes operability. This study evaluated yttrium-90 selective internal radiation therapy ( ⁹⁰ Y-SIRT) for controlling right-liver tumors and inducing compensatory left-lobe hyperplasia. Results: Thirty-seven patients (29 hepatocellular carcinomas, 2 intrahepatic cholangiocarcinoma, 6 liver metastasis of colorectal cancer) with right-liver tumors underwent ⁹⁰ Y-SIRT. Tumor volume decreased significantly by 133 mL at 1 month and 206 mL at 3 months post-treatment (both P<0.001). Right-liver volume reduction averaged 182 mL at 1 month (P<0.001) and 300 mL at 3 months (P<0.001). Concurrently, left-liver volume increased by 55 mL (P<0.001) and 127 mL (P<0.001) at 1 and 3 months, respectively, while FLR percentage rose by 5.8% (P<0.001) and 11.9% (P<0.001). Per mRECIST criteria, 3-month imaging revealed an objective response rate (ORR) of 78.4% and disease control rate (DCR) of 91.9%. In 14 patients downstaged to resection/transplantation, ICG-R15 levels remained stable, confirming preserved liver reserve function post-90Y-SIRT. These findings demonstrate ⁹⁰ Y-SIRT effectively controls right-lobe tumor progression and stimulates compensatory left-lobe hypertrophy, enabling FLR expansion. The treatment achieved high ORR, significant tumor downstaging, and pathological necrosis without compromising hepatic functional reserve. Conclusions: 90Y-SIRT represents a safe and efficacious strategy to convert initially unresectable patients into surgical candidates.