03:54 PM Abstract No. 118 Radiation segmentectomy or transarterial chemo-embolization followed by stereotactic body radiation therapy for hepatocellular carcinoma: toxicity and survival

The objective of this study is to compare hepatic function parameters and mortality among hepatocellular carcinoma (HCC) patients treated with radiation segmentectomy (RS) with transarterial yttrium-90 beads or transarterial chemo-embolization followed by stereotactic body radiation therapy within 6 months (TSBRT). We reviewed all HCC patients treated at our institution from January 2010 to September 2017 with RS (n=71, 66% male, median age 67 years) or TSBRT (n=50, 66% male, median age 64 years). Short-term follow-up (STFU) was derived from the first labs at 3-9 months after treatment, and longer term follow-up (LTFU) was derived from first labs at 9-15 months. Time points were compared utilizing Wilcoxon signed rank test or paired t-test. Adverse events were recorded per SIR guidelines. Cox multivariate regression survival analysis was used to evaluate overall survival time (OST) after RS or TSBRT. Target tumor size was larger for RS than in TSBRT (median 5.2 v 2.9 cm, p<0.001). STFU median was 4.4 mo (STD 1.2), and LTFU median was 10.1 mo (STD 1.2). Baseline model for end-stage liver disease (MELD) and albumin-bilirubin (ALBI) scores were not significantly different (median MELD 8.5 v 9.2, p=0.39; mean ALBI -2.34 v -2.27, p=0.47). At STFU, there was significant increase in both parameters for RS (MELD rise 1.0, p<0.001; ALBI rise 0.3, p<0.001) and TSBRT (MELD rise 1.4, p=0.002; ALBI rise 0.2, p<0.001). At LTFU, RS hepatic parameters remained significantly elevated from baseline (MELD rise 1.8, p<0.001; ALBI rise 0.2, p<0.001) while TSBRT trended higher (MELD rise 1.9, p=0.08; ALBI rise 0.1, p=0.14). There were 9 and 7 SIR grade C or higher events in the RS and TSBRT groups. There were 29 deaths (median OST 14.8 mo, median follow up for living patients 18.3 mo). Multivariate survival analysis revealed tumor size as the only independent predictor of OST (HR 1.4 per cm, p<0.001). Hepatic function decline was similar for RS and TSBRT at STFU, but only RS patients demonstrated significant decline at LTFU. Adverse event profiles were similar. Of all the baseline characteristics, tumor size was the only predictor of survival in both groups.