Abstract No. 566 Yttrium-90 radioembolization for unresectable neuroendocrine liver metastases: report in an Asian population

Abstract

Yttrium-90 radioembolization is one of the intra-arterial therapies for unresectable neuroendocrine liver metastases (NELM). However, the data regarding Asian population is lacking. The aim of this study is to present the efficacy of Yttrium-90 radioembolization (Y90-RE) in the treatment of NELM and identify prognostic factors for survival in pure Asian population. This retrospective study was approved by the institutional review board and requirement for informed consent was waived. Between May 2008 and December 2016, twenty-three patients (13 men, 10 women; age range, 33 – 77 years) with NELM treated with Y90-RE at our institute were enrolled. Response to therapy was assessed by RECIST criteria by using periprocedural MR imaging. Posttreatment three-month radiologic response and survival were measured as the clinical end points. Of the 23 patients, 31 Y90-RE sessions were performed with a mean delivered dose 1.5 ± 0.6 GBq (range, 0.5 – 3.0 GBq) of first treatment and 2.6 ± 1.6 GBq (range, 0.7 – 5.0 GBq) of second treatment. In 3 and 6 months imaging follow-up, 8 (34.8%) and 8 (34.8%) patients had radiographic partial response to treatment, 9 (39.1%) and 12 (52.2%) had stable disease, 3 (13.0%) and 1 (4.3%) developed progressive disease. Median survival was 37.4 months, with 1-, 2-, and 3-year overall survival rates of 78.3%, 56.5%, and 30.4%, respectively. In univariate analysis, resection of primary tumor (P = 0.023), post Y90 local regional treat (LRT) (P = 0.019) and 3 months disease control (P = 0.0) were associated with good survival. On the contrary, high-grade (grade 3) histopathology of tumor (P = 0.008), tumor burden > 50% (P = 0.013), estimated absorbed tumor dose 103Gy (P = 0.030) and progressive radiographic response at 3 months (P = 0.005) were related to worse survival. Multivariate analysis revealed that disease control at 3 months (HR 0.002, P = 0.031), primary tumor resection (HR 0.035, P = 0.023), Post Y90 LRTs(HR 0.031, P = 0.001)were a predictor for better survival outcome. In Asian NELM population who underwent Y90-RE, primary tumor resection, 3 month tumor response, and post Y90 LRTs can predict survival outcome.