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

<b>Background/Objectives</b>: 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. <b>Objective</b>: 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. <b>Methods</b>: 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. <b>Results</b>: 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. <b>Conclusions</b>: 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.