Dose–response relationship in patients who received transarterial radioembolization with Y-90 resin microspheres for hepatocellular carcinoma

Objective The aim of this study is to analyze the dose–response relationship in hepatocellular carcinoma (HCC) patients who received transarterial radioembolization (TARE) with Y-90 resin microspheres. Methods Patients who received TARE with Y-90 resin microspheres using multicompartment dosimetry between February 2020 and December 2024 were included in the analysis. A total of 46 lesions from 21 patients were included in the dose-response analysis. Multicompartment dosimetry was performed for all lesions in the perfused area. Additionally, the mean tumor absorbed dose (TAD), whole-liver absorbed dose, and perfused-liver absorbed dose were calculated. Results All the patients received Y-90 resin microspheres with a lobar or segmental approach. Median tumor volume was calculated as 9.4 cm³ (min–max: 1–1674). During the third-month evaluation, 21 lesions were responders. In the receiver operating characteristic analysis, a 104 Gy cutoff for mean TAD [AUC: 0.693, 95% confidence interval (CI): 0.532–0.853, P = 0.018] was calculated for response, with 76% sensitivity and 64% specificity. For the prediction of complete response, we found a 159 Gy cutoff for mean TAD (AUC: 0.776, 95% CI: 0.598–0.953, P = 0.002), with 70% sensitivity and 79% specificity. Conclusion We demonstrated a strong relationship between absorbed tumor dose and treatment response in HCC patients who received TARE with Y-90 resin microspheres. Delivery of approximately 100 Gy mean absorbed dose to the tumor is needed to achieve a response. Increasing the TAD to ~160 Gy would be expected to result in a complete response.