# Efficacy and Safety of Selective Internal Radiation Therapy (SIRT) for Liver Metastases in Breast Cancer: An Umbrella Review

## TL;DR

This umbrella review examines how effective and safe SIRT is for treating liver metastases in breast cancer patients, finding it helpful with manageable side effects, but more research is needed.

## Contribution

A systematic synthesis of existing reviews on SIRT for breast cancer liver metastases, highlighting efficacy and safety while identifying research gaps.

## Key findings

- SIRT shows objective response rates between 36% and 61% in breast cancer liver metastases.
- Disease control rates range from 78% to 96%, with generally favorable toxicity profiles.
- Heterogeneity in patient selection and microsphere types limits definitive conclusions.

## Abstract

Hepatic metastases are a frequent manifestation in advanced breast cancer and are associated with limited therapeutic options and poorer prognosis. Selective Internal Radiation Therapy (SIRT) is a locoregional treatment that delivers radiation directly to liver tumors through the bloodstream. This umbrella review summarizes the results of several previous studies that analyzed how effective and safe SIRT is for patients with breast cancer that has spread to the liver. The findings suggest that SIRT can help control the disease in many cases and has manageable side effects. However, more high-quality research is needed to fully understand how and when to use this treatment.

Background/Objectives: Liver metastases in breast cancer patients are associated with poor prognosis and limited therapeutic options. Selective Internal Radiation Therapy (SIRT), also known as transarterial radioembolization (TARE), has emerged as a loco-regional treatment modality, particularly in cases refractory to systemic therapies. Objective: To systematically review and synthesize evidence from existing systematic reviews and meta-analyses on the efficacy and safety of SIRT in breast cancer patients with liver metastases. Methods: A comprehensive literature search was conducted in PubMed using predefined keywords related to SIRT and breast cancer, restricted to systematic reviews and meta-analyses. Inclusion criteria were reviews evaluating SIRT in breast cancer patients with hepatic metastases, reporting on efficacy (e.g., objective response rate, disease control rate, overall survival) and/or safety outcomes. The quality of included reviews was assessed using AMSTAR 2. Results: Seven systematic reviews and meta-analyses were included. Reported objective response rates (ORRs) ranged from 36% to 61%, and disease control rates (DCRs) from 78 to 96%. Toxicity profiles were generally favorable, with limited grade 3–4 adverse events. Some heterogeneity was noted in patient selection, types of microspheres used (glass vs. resin), and outcome definitions. Conclusions: SIRT appears to be a promising option for breast cancer patients with liver metastases, particularly in the setting of treatment resistance. However, heterogeneity among available studies and the lack of prospective randomized trials limit definitive conclusions. Further high-quality studies are warranted.