1Natalie Rothenberger, 2,3Shakthi Kumaran Ramasamy,  2Thuong Van Ha, 2Steven Zangan, 2Osman Ahmed

1Geisinger Commonwealth School of Medicine, 2University of Chicago, 3Loyola University Medical Center

Background(s):

To evaluate the objective response rate (ORR), time to progression (TTP), and overall survival (OS) in patients with unresectable solitary HCC who were treated with 90Y glass microspheres infused at a segmental level.

Material(s) and Method(s):

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, <5cm 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 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. Kaplan-Meier analysis was used to evaluate OS.

Result(s):

Median tumor size was 3 cm (range: 1.0-4.8 cm) in the 35 patients studied, with 25.7% being Eastern Cooperative Oncology Group (ECOG) 0 and 62.9% ECOG 1. A majority of patients (88.5%, 31/35) were Barcelona Clinic Liver Cancer (BCLC) stage C, with one patient classified as BCLC-A and BCLC-0 each. For 34.2% (12/35), TARE functioned as a bridge to transplantation. Patients who received a transplant exhibited a median pathologic necrosis of 98% (IQR 7.5). At 12 months post-TARE, the combined ORR for local and overall mRECIST 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 AE’s following treatment, 80% were Grade 1, one patient experienced a Grade 4, and all events resolved within one month of treatment. Total OS at 1 year was 97.1%, whereas patients who underwent OLT had an OS of 100%.

Conclusion(s):

Segmental TARE was a safe and effective treatment for solitary unresectable HCC less than 5cm. When used as a bridge to transplant, near complete pathologic necrosis rates of treated lesions were observed on explant.