Yttrium-90 Glass Microsphere Transarterial Radioembolization for Patients with Unresectable Liver-Dominant Breast Cancer Metastasis

Abstract

Transarterial radioembolization (TARE) using Yttrium-90 (Y90) microspheres is a potential therapeutic option for treatment-refractory, unresectable, liver-dominant breast cancer metastases (LdBM). We hypothesized that Y90 TARE is an effective and safe treatment for delaying progression in patients with LdBM. In this IRB approved (MCC 18294) study, we retrospectively analyzed institutional database to identify patients with unresectable and chemotherapy-refractory LdBM who underwent Y90 TARE. We extracted patient demographics, systemic therapy details and imaging studies for response assessment. Liver function tests, CA15-3 level, Albumin-Bilirubin (ALBI) and Model for end-stage liver disease (MELD) score were assessed at baseline, 1- and 3-months post TARE to evaluate for hepatotoxicity. Hepatic progression-free (hPFS) and overall survival (OS) were estimated using Kaplan-Meier analysis, and compared using log-rank test. Cox regression was performed to evaluate the effect of predictors on defined outcomes. Maximum toxicity grade was reported using Common Terminology Criteria for Adverse Events version 5. Between 2010-2019, 32 patients with LdBM underwent 51 TARE sessions with Y90 glass microsphere. All patients progressed through systemic therapy. Median age was 61 years (range 27-81). Interval to develop liver metastasis from initial breast cancer diagnosis was 5-years (median). Median follow-up duration after TARE was 11 months (range, 1-44). 18 patients had sequential bilobar treatment, 1 sequential segmental, 9 unilobar right, 1 unilobar left, 2 segmental and 1 whole-liver single session TARE. Median hPFS and OS after TARE were 7-months (95% CI 5.0–9.1) and 13 months (95% CI 9.2–16.8), respectively. The 6-months and 1-year actuarial hPFS were 52% and 21%; and 1-year and 2-year OS were 58.5%, and 35.7%, respectively. Factors independently predicting worse hPFS were age <60 years (6-month hPFS 41.3% vs 62.5%, p = 0.04) and bilobar disease (33.3% vs. 68.8%, p = 0.005). On multivariate analysis, bilobar disease (p = 0.01) and high baseline CA 15-3 (p = 0.05) were predictors of longer OS. No significant change was noted in ALBI, MELD, total bilirubin, albumin and alkaline phosphatase levels at 1- and 3-months post-TARE. Grade 3 toxicity was noted in 3-patients (9.4%), all received sequential bilobar treatment, necessitating hospitalization for pain (2-patients), and worsening liver function (1-patient). The 30-day mortality was 3.1%; 1 patient died from radioembolization-induced liver disease. For patients with therapy-refractory unresectable LdBM, Y90 TARE is effective and relatively safe. TARE can potentially delay progression allowing patients with LdBM to continue systemic therapy longer.