3:36 PM Abstract No. 26 Longitudinal study of progression patterns of hepatocellular carcinoma patients undergoing Y90 radiation segmentectomy

Abstract

We aim to study oncologic outcomes of hepatocellular carcinoma (HCC) patients undergoing ablative segmental radioembolization (RS/Y90). We hypothesize that ablative RS provides excellent disease control with limited local progression. With IRB approval, we performed a retrospective review of HCC patients who received Y90 per tumor board decision between 2004 and 2017. Inclusion criteria were Child-Pugh A patients with solitary HCC who underwent ablative radiation segmentectomy (RS) without subsequent surgical treatments. All imaging follow-up scans were reviewed until death, loss to follow-up or September 2019. Objective tumor response rates were assessed by mRECIST. Pattern of HCC progression was classified as treated tumor progression vs. new tumor development. Time to progression and overall survival (OS) were estimated using Kaplan-Meier method. 69 (44 male) patients met inclusion criteria; mean age 72 years. Median tumor size was 2.6 cm (range, 1.1–7.8). All patients underwent ablative RS with target dose > 190 Gray. Tumor response was achieved in 66 (96%) patients: 42 (61%) had complete response and 25 (36%) had partial response. Median time to last follow-up was 42 (range, 1-150) months. 7 patients (10%) developed local progression; median time to local progression was not reached at 130 months follow-up, with 2, 5 and 10-year local tumor control rate of 91%, 85% and 85% respectively. 25 (36%) patients developed new tumors at median time to development of new tumors of 42.3 (CI: 34.6-68.9) months. Out of 27 (39%) patients who progressed during the entire follow-up period, new lesions were the first sign of progression in 20 (29%). At time of last follow-up, 2 patients (3%) had developed malignant vascular invasion and 2 (3%) had developed extrahepatic metastases. Median OS was not reached at 150 months, with 5 and 10-year survival rates 68% and 54%. In a cohort of non-surgical candidates, RS has shown excellent outcomes in disease control and survival, comparable to reported outcomes for resection and transplant. The majority of progression patterns following ablative RS are in the form of new tumors rather than recurrence or progression of treated tumors.