In a large retrospective cohort study conducted by Lebow et al., data on 98 patients with BMs from different cancer types (NSCLC, BC, HER2 amplified Esophageal and/or gastric cancer, HER2 amplified Salivary) who received at least one course of stereotactic RT (SRT) concurrently with T-DM1, T-DXd, or SG were reviewed. This evidence concerns the gene ERBB2 and breast cancer.