3:09 PM Abstract No. 238 Bland versus Y90 embolization: a retrospective analysis of outcomes in hepatic neuroendocrine metastases

Both transarterial radioembolization (TARE) and bland transarterial embolization (TAE) have been shown in single-institution studies to have a substantial radiologic response for a variety of liver tumors, including neuroendocrine metastases. However, randomized controlled trials have not yet been published comparing these modalities. The purpose of this study was to compare outcomes between TARE and TAE when performed for neuroendocrine metastases. Retrospective review of our procedural database demonstrated that 132 unique patients had been treated with embolotherapy for neuroendocrine metastases to the liver between 2005 and 2019. Of these, 106 were treated exclusively with one of the two modalities; patients who underwent both treatments during the review period were excluded. Radiologic response was assessed at the 3-month follow-up imaging based on mRECIST criteria and compared with the chi square test. Time to (hepatic) progression (TTP), (hepatic) progression-free survival (PFS), and overall survival (OS) were analyzed using the Kaplan-Meier technique and compared with the log rank test. Baseline demographics and tumor characteristics such as WHO grade, presence of bilobar disease, and prior resection of the primary tumor were similar between groups. Radiologic response rate at three months was 70% in the bland group and 73% in the Y90 group (P = 0.9). The median TTP was significantly longer after TARE than TAE (18.4 vs. 10.2 months, P = 0.025). The median hepatic PFS from first embolotherapy was 9.1 months in the TAE group and 10.2 months in the TARE group (P = 0.52). The median OS was 30.2 months in the TAE and 33 months in the TARE group (P = 0.34). Of the baseline characteristics compared between groups, only WHO grade was an independent predictor of OS (59.1 vs. 32.1 vs. 10.3 months in grade 1, 2, and 3 disease respectively; P <0.001). TARE and TAE demonstrated similar PFS and OS, despite a significantly longer TTP with TARE. WHO grading was the only significant predictor of survival in these patients undergoing embolotherapy.