Yttrium-90 Radioembolization for Unresectable, Chemoresistant Breast Cancer Liver Metastases: A Large Single-Center Experience of 40 Patients.

Introduction: There are a paucity of data on the treatment of unresectable, chemoresistant breast cancer liver metastases (BRCLM) with yttrium-90 (Y90) radioembolization. Methods: Forty patients underwent resin-based Y90 radioembolization for unresectable, chemoresistant BRCLM between 2006 and 2012 in a single institution. All patients were followed up with imaging studies at regular intervals as clinically indicated until death. Radiologic response was evaluated with the Response Criteria in Solid Tumors criteria. Clinical toxicities were prospectively recorded as per the National Cancer Institute Common Toxicity Criteria. Survival was calculated by the Kaplan-Meier method and potential prognostic variables were identified on univariate and multivariate analysis. Results: Follow-up was complete in all patients. The median follow-up was 11.2 (range 0.6-30.5) months and the median survival after Y90 radioembolization was 13.6 months, with a 24-month survival of 39 %. On imaging follow-up of 38 patients who survived beyond 1 month of treatment, a complete response (CR) to treatment was observed in two patients (5 %), partial response (PR) in 10 patients (26 %), stable disease (SD) in 15 patients (39 %), and progressive disease (PD) in 11 patients (29 %). Two factors were associated with an improved survival on multivariate analysis: CR/PR to treatment (vs. SD vs. PD; p < 0.001) and chemotherapy after radioembolization (vs. no chemotherapy; p = 0.004). Sixteen patients (40 %) developed clinical toxicity after treatment; all complications were minor grade I/II and resolved without active intervention. Conclusion: This study provides supportive evidence of the safety and efficacy on Y90 radioembolization for the treatment of unresectable, chemoresistant BRCLM. Further prospective investigation is required to assess the suitability of this treatment in this population. [ABSTRACT FROM AUTHOR]