Efficacy and Safety of Radiation Segmentectomy with 90Y Resin Microspheres for Hepatocellular Carcinoma

Background: Limited data are available on radiation segmentectomy (RS) for treatment of hepatocellular carcinoma (HCC) using yttrium 90 (90Y) resin microsphere doses determined by using a single -compartment medical internal radiation dosimetry (MIRD) model. Purpose: To evaluate the efficacy and safety of RS treatment of HCC with 90Y resin microspheres using a single -compartment MIRD model and correlate posttreatment dose with outcomes. Materials and Methods: This retrospective single -center study included adult patients with HCC who underwent RS with 90Y resin microspheres between July 2014 and December 2022. Posttreatment PET/CT and dosimetry were performed. Adverse events were assessed using the Common Terminology Criteria for Adverse Events, version 5.0. Per -lesion and overall response rates (ie, complete response [CR], objective response, disease control, and duration of response) were assessed at imaging using the Modified Response Evaluation Criteria in Solid Tumors, and overall survival (OS) was assessed using Kaplan -Meier analysis. Results: Among 67 patients (median age, 69 years [IQR, 63-78 years]; 54 male patients) with HCC, median tumor absorbed dose was 232 Gy (IQR, 163-405 Gy). At 3 months, per -lesion and overall (per -patient) CR was achieved in 47 (70%) and 41 (61%) of 67 patients, respectively. At 6 months (n = 46), per -lesion rates of objective response and disease control were both 94%, and per -patient rates were both 78%. A total of 88% (95% CI: 79 99) and 72% (95% CI: 58, 90) of patients had a per -lesion and overall duration of response of 1 year or greater. At 1 month, a grade 3 clinical adverse event (abdominal pain) occurred in one of 67 (1.5%) patients. Median posttreatment OS was 26 months (95% CI: 20, not reached). Disease progression at 2 years was lower in the group that received 300 Gy or more than in the group that received less than 300 Gy (17% vs 61%; P = .047), with no local progression in the former group through the end of follow-up. Conclusion: Among patients with HCC who underwent RS with 90Y resin microspheres, 88% and 72% achieved a per -lesion and overall duration of response of 1 year or greater, respectively, with one grade 3 adverse event. In patients whose tumors received 300 Gy or more according to posttreatment dosimetry, a disease progression benefit was noted. (c) RSNA, 2024