Segmental Yttrium-90 Radioembolization as an Initial Treatment for Solitary Unresectable HCC

Abstract Objectives  To evaluate the objective response rate (ORR), time to progression (TTP), and overall survival (OS) in patients with unresectable solitary HCC less than 5 cm who were treated with 90 Y glass microspheres infused at a segmental level. Materials and Methods  Single-institution retrospective study of 35 patients with unresectable HCC deemed not suitable for percutaneous ablation who underwent segmental transarterial radioembolization (TARE) treatment. Eligibility criteria included patients with solitary, unilobar, < 5 cm unresectable HCC lesions who underwent TARE as a primary treatment strategy between November 2012 and April 2020. Imaging follow-up was performed on each patient at 3-, 6-, and 12 months post-treatment. Local and the overall tumor response was evaluated using mRECIST criteria, and primary endpoints were ORR, TTP, and OS. Adverse events (AEs) were graded for severity using the Common Terminology Criteria for Adverse Events (CTCAE) v.5.0. Statistical Analysis  Patient demographics, baseline characteristics, and treatment characteristics were analyzed using descriptive statistics. Predictors of survival were analyzed with Cox proportional hazards regression. Kaplan–Meier analysis was used to evaluate OS. Results  Median tumor size was 3 cm (range: 1.0-4.8 cm) in the 35 patients studied, with 25.7% (9/35) being the Eastern Cooperative Oncology Group (ECOG) 0 and 62.9% (22/35) ECOG 1. Most patients (88.5%, 31/35) were of the Barcelona Clinic Liver Cancer (BCLC) stage C, with one patient each classified as BCLC-A and BCLC-0, respectively. For 34.2% (12/35), TARE functioned as a bridge to transplantation. Transplanted patients exhibited a median pathologic necrosis of 98% (IQR 7.5). Combined ORR for local and overall mRECIST at 12 months post-TARE was 94.3% and 85.7%, respectively. All patients had a mean local TTP of 11.9 months (CI: 2.7–21.0) and global TTP of 13.2 months (CI: 6.4–20.0). Among the 14.3% (5/35) of patients who experienced AEs following treatment, 80% (4/5) were Grade 1, one patient experienced a Grade 4, and all events resolved within 1 month of treatment. Total OS at 1 year was 97%, whereas patients who underwent OLT had an OS of 100%. Conclusion  Segmental TARE was a safe and effective treatment for solitary unresectable HCC less than 5 cm. When used as a bridge to transplant, explants showed near complete pathologic necrosis of treated lesions.