Relationship of radiation dose to efficacy of radioembolization of liver metastasis from breast cancer

•Higher radiation dose to breast cancer liver metastases during radioembolization is associated with objective response.•A dose threshold to tumor of 79.5 Gy is proposed to achieve objective response.•Longer survival is associated with objective response.•Survival is shorter in patients with poor baseline liver function, bilobar tumors, and hepatotoxicity from radioembolization.•Accurate pre-treatment dosimetry may help optimize response to radioembolization of breast cancer liver metastasis. To determine the relationship of tumoral and nontumoral radiation dose to response and toxicity after transarterial radioembolization (TARE) of breast cancer liver metastasis. This retrospective study evaluated all patients with breast cancer liver metastases treated with TARE (2/2011—6/2019). Extent of disease was measured as unilobar or bilobar on baseline PET/CT prior to TARE. Response was assessed for targeted regions with modified PERCIST criteria on first follow-up PET/CT. Tumoral and nontumoral liver dosimetry was evaluated by performing volumetric segmentation on post-TARE Bremsstrahlung SPECT/CT. ≥Grade 3 hepatotoxicity was defined as ≥grade 3 bilirubin/AST/ALT elevation or ascites requiring intervention. Fisher’s exact tests, Wilcoxon rank sum tests, and Kaplan-Meier survival analysis were performed. Among 64 women, 60 patients had pre- and post-TARE PET/CT, of whom 46/60 (77 %) achieved objective response (OR). Responders received higher tumoral dose with a median (interquartile range) of 167 (96–217) vs. 54 (45–62) Gy (p