Survival outcomes of beta-blocker usage in HER2-positive advanced breast cancer patients: a retrospective cohort study.

Our study provides important evidence that BB use potentially has a negative effect on patients with HER2-positive advanced breast cancer. Nevertheless, despite the study's results, cardiovascular disease (CVD) should be appropriately treated in patients with HER2-positive advanced breast cancer. Other types of drugs can be used to treat CVD, but BB use should be avoided. Large real-world database and prospective studies should be conducted to validate the results of this study.