2225 - Locoregional Treatment Outcomes of Hepatocellular Carcinoma Defined by Large Tumor Size or Macrovascular Invasion with Yttrium-90 Radioembolization and Stereotactic Body Radiation Therapy
Presenter(s)
K. M. Banson1, A. Singh2, C. Oh3, S. Sil1, A. Mahadevan1, and C. Hill4; 1Department of Radiation Oncology, NYU Langone Health, New York, NY, 2Department of Integrative Biology and Physiology, University of California–Los Angeles, Los Angeles, CA, 3Biostatistics, Department of Population Health, NYU Langone Health, New York, NY, 4Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
Purpose/Objective(s): Patients (pts) with hepatocellular carcinoma (HCC) often present with advanced stage and unfavorable risk features, precluding them from resection or liver transplant (LT). Liver directed therapies (LDT) such as yttrium-90 radioembolization (Y-90) or stereotactic body radiotherapy (SBRT) are preferentially utilized for definitive intent, bridging, or downstaging. Personalized Y-90 dosimetry with LEGACY showed promise with ablative dosing although predominantly in median tumor sizes <=3 cm without macrovascular invasion (MVI). RTOG 1112 demonstrated a survival benefit of SBRT over sorafenib alone with a median tumor size of 7.8 cm and MVI rate of 74%. Herein, we report institutional outcomes of HCC >=3 cm with and without MVI treated with Y-90 or SBRT.
Materials/Methods: This single-institution retrospective study included HCC pts treated between August 2017 and October 2025 with SBRT and Y-90. Primary outcomes were local control (LC) and overall survival (OS) stratified by LDT. Survival time was defined from first LDT to death or last follow-up. Kaplan–Meier methods estimated LC and OS. Groups were compared using log-rank tests.
Results: Fifty-seven pts with 59 lesions received first LDT (Y-90: n = 40; SBRT: n = 19). At time of first LDT, the majority had CP-A5-6 (73%) and AL-BI grade 2 (61%) liver function. The median size was 5.3 for SBRT and 5.5 cm for Y-90. Compared to Y-90, pts treated with SBRT had a higher MVI rate (53% vs 10%), prior systemic therapy (58% vs 0%), and greater median AFP burden (23.0 vs 10.0). The median follow-up was 19.3 months (mo.) for SBRT and 32.5 mo. for Y-90. The 1-year LC rates were 68.7% for SBRT and 35.6% for Y-90 (p = 0.2). On adjusted multivariable analysis (MVA), Y-90 demonstrated a six-fold increase in local failure (HR 6.6, p =0.02). Of the tumors that failed locally after Y-90, 45.8% and 54.2% received lobar and segmental Y-90, respectively. Larger tumor size (HR 1.3, p =0.006) was associated with LF. One-year OS was 72.0% for SBRT and 94.7% for Y-90 (log-rank p < 0.001). On univariate analysis, MVI (HR 5.3, p < 0.001), higher AFP (HR 1.2, p = 0.03), and resection/LT (HR 0.1, p = 0.04) were associated with OS, but none were significant on MVA. After Y-90, 5 pts underwent resection/LT vs 2 pts after SBRT. A second LDT was delivered to 22 lesions, with a median time to second LDT of 5.1 and 7.3 mo. for Y-90 and SBRT, respectively. Liver toxicity was low overall with 3-mo. post-LDT AL-BI scores stable or decreased in 63% vs 89% for SBRT and Y-90 respectively.
Conclusion: For large size HCC, durable locoregional control may be more difficult to achieve with Y-90 due to the inhomogeneous delivery of ablative doses compared to more homogenous tumor coverage with SBRT. For interval waiting times <=6 mo. to surgery, Y-90 may be logistically advantageous. Prospective trials are needed to guide modality selection in large size HCC with and without MVI.