4:12 PM Abstract No. 145 Yttrium-90 radiation segmentectomy for hepatic metastases: a multi-institutional study of safety and efficacy

Abstract

Yttrium-90 (Y-90) radiation segmentectomy has shown great promise for treatment of localized primary liver cancer. This study assessed outcomes of segmental Y-90 radioembolization for hepatic metastases, not amenable to surgical resection or ablation. A retrospective review was performed on patients with hepatic metastases treated with radiation segmentectomy at two institutions over 6 years (2012-2018). 32 patients with 53 tumors (14 patients with >1 tumor) underwent segmental radioembolization, with ablative-level doses exceeding 200 Gy to perfused tissue. Patients were not candidates for surgical resection or thermal ablation due to medical comorbidities, presence of extrahepatic disease, tumor size, or tumor location. Hepatic metastases were from colorectal cancer (34%), neuroendocrine tumors (28%), sarcoma (19%), and others (19%). 62% of patients had liver-only disease, and 38% had liver-dominant disease. 75% of patients had an ECOG performance status of 0. All patients had normal liver function tests at baseline. With the exception of biologic agents, ongoing systemic chemotherapy was not discontinued. Toxicity, tumor response, tumor progression, and survival were assessed. Median tumor size was 3.6 cm (range, 1.2-6.1 cm). Toxicity rates were low, with no hepatic-related CTCAE grade 3 or 4 toxicity and a 6% rate of CTCAE grade 3 leukopenia. Target tumor objective RECIST response rate was 74% (19% complete response, 55% partial response) and disease control was 89%. For patients with hypervascular tumors (n = 22), target tumor objective mRECIST response rate was 100%, with a complete response in 86%. During a median follow-up of 12 months, overall survival was 94% and target tumor progression occurred in 25% of treated tumors. Y-90 radiation segmentectomy for hepatic metastases demonstrates high rates of tumor response with low rates of target tumor progression. Toxicities are minimal, despite many patients receiving concurrent chemotherapy. Radiation segmentectomy should be considered for patients with liver-dominant metastatic disease who are not ideal candidates for surgical resection or ablation.