Tumor-Absorbed Dose, Metabolic Response, and Survival after Yttrium-90 Radioembolization in Patients with Breast Cancer Liver Metastases.

[PURPOSE] To evaluate the association between tumor-absorbed dose (TAD) relative to response and survival among patients with breast cancer liver metastasis (BCLM) treated with yttrium-90 (Y) transarterial radioembolization (TARE).

[MATERIALS AND METHODS] Between August 2016 and August 2024, patients with BCLM who underwent Y TARE with glass microspheres were retrospectively included. Primary outcomes were overall survival (OS) and hepatic progression-free survival (hPFS). The secondary outcome was the objective response rate. Response to treatment was assessed using Positron Emission Tomography (PET) Response Criteria in Solid Tumors. Patients were divided into 2 groups as responders and nonresponders.

[RESULTS] Twenty-six women with a mean age of 57.9 years (SD ± 13.8) met the inclusion criteria. The median OS and hPFS for all patients were 6.1 months (interquartile range [IQR], 4.3-9.0 months) and 4.2 months (IQR, 2.5-5.6 months), respectively. The median TAD for responders and nonresponders were 157 Gy and 150 Gy, respectively (P = .768). The median OS and hPFS for responders versus nonresponders were 8.3 months (IQR, 5.5-14.8 months) and 4.1 months (IQR, 3.1-6.3 months) versus 4.0 months (IQR, 2.5-4.5 months) and 2.1 months (IQR, 1.3-2.7 months), respectively (P = .025 and P = .210, respectively). TAD showed a significant OS benefit above 145 Gy but did not change hepatic hPFS (P = .024 and P = .397, respectively).

[CONCLUSIONS] Imaging response was modestly correlated with OS, and TAD was not correlated with response in this series.