Survival Outcomes Following Yttrium-90 and Holmium-166 Transarterial Radioembolization for Hepatocellular Carcinoma.

Background/Objectives: Transarterial radioembolization (TARE) plays an increasing role in the treatment of hepatocellular carcinoma (HCC). Several isotope platforms have been introduced; however, comparative data remain limited. We aimed to compare outcomes following Holmium-166 (Ho-166) and Yttrium-90 (Y-90) TARE in HCC patients. Methods: We retrospectively analyzed a prospectively maintained cohort of HCC patients treated with Ho-166 or Y-90 TARE between 2022 and 2024. Tumor burden and treatment response were assessed using contrast-enhanced CT or MRI. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method and further evaluated using multivariable Cox regression analyses adjusted for baseline confounders. Results: A total of 73 patients were analyzed, including 39 treated with Y-90 and 34 with Ho-166 TARE. Median follow-up duration was 20.9 months. No significant differences in OS or PFS were observed between treatment groups. Response outcomes, including objective response rate, complete response rate, and duration of response, were also comparable between groups. In the overall cohort, median OS was not reached in Barcelona Clinic Liver Cancer (BCLC) A or B patients and was 12.9 months in BCLC C patients. Median PFS was 20.1, 11.7, and 6.1 months in BCLC A, B, and C patients, respectively. Conclusions: Ho-166 and Y-90 TARE achieved favorable outcomes across different BCLC stages without significant differences in survival, treatment response, or duration of response between the two platforms. These findings further support the role of TARE in the management of patients with HCC.