Adjuvant stereotactic body radiotherapy (SBRT) for resected primary and metastatic liver cancers.

Abstract

487 Background: Stereotactic body radiotherapy (SBRT) has been shown to be a safe and effective treatment for hepatobiliary cancers. However, little is known about the efficacy of adjuvant SBRT for resected liver tumors with positive margins. We examined the characteristics and outcomes of patients who received adjuvant SBRT for both primary and metastatic cancers of the liver. Methods: We retrospectively reviewed the charts of patients who had received liver SBRT from 2009-2015 at our institution. During that time frame, 11 patients were identified as having received adjuvant SBRT post resection. Patient data such as age, gender, portal vein thrombosis, cirrhosis, ECOG performance status, prior liver directed therapies, and SBRT dose were collected. Descriptive statistics were used for analysis given the small number of patients in this series. Results: Median age at the time of treatment was 63 years (range 51-79), and the majority of patients (72.7%) were male. Seven tumors (63.6%) were hepatocellular carcinomas, and 4 (36.4%) were adenocarcinomas. Of the tumors with adenocarcinoma histology, 3 were cholangiocarcinomas and one was metastatic colorectal cancer. Ten patients (90.9%) were treated for positive margins, and one was treated for inferior vena cava (IVC) invasion. Seven patients (63.6%) had no other liver-directed treatment prior to adjuvant SBRT. Two patients received systemic therapy prior to SBRT. Median EQD2 was 83.3 Gy (range 60-126), and 81.8% of patients received 5 fractions. There were no grade 3 or above late toxicities from treatment. Median follow-up was 14.1 months (range 5.4-38.1). None of the treated tumors progressed locally. Six patients (54.5%) progressed elsewhere in the liver, and one patient experienced distant metastatic progression. One patient experienced both intrahepatic progression and distant metastatic progression. Conclusions: Adjuvant SBRT appears to be a safe and feasible adjuvant treatment in patients with primary liver resection for either primary liver cancer or metastatic disease who are at high risk of recurrence.