Pre-diagnosis beta-blocker use and breast cancer survival outcomes: a systematic review.
Abstract
Background/Aim: While it is biologically plausible that pre-cancer diagnosis use of beta-blockers could potentially prevent the development and reduce the growth of cancer tumours, existing evidence regarding this has not been synthesised. This review aimed to gain a greater understanding of the effect of pre-diagnosis beta blocker use on survival in breast cancer patients.
Methods: A systematic search of PubMed, Web of Science and Embase was conducted for studies published 2010-2022, that reported breast cancer-specific and/or overall survival by pre-diagnosis beta-blockers use (users vs non-users) in people diagnosed with breast cancer. Results were exported into Covidence software and screened against pre-defined eligibility criteria. Key information was extracted using a standardised form in Excel, including the adjusted hazard ratios. PRISMA guidelines were used.
Results: Seven articles reported the association between pre-diagnosis beta-blocker use and survival in people with breast cancer. Three articles reported on overall survival; all reporting small and non-significant point estimates (HRs ranged 1.02 - 1.13). Six of the seven articles reported on breast cancer-specific survival. These studies suggest that pre-diagnosis beta blocker use may have a protective effect (HR range 0.19-0.94), although only three of these studies were statistically significant (HR 0.19-0.42, p<0.05). Two studies reported the association between survival by type of beta-blocker used prior to breast cancer diagnosis; indicating that non-selective beta-blockers may be more effective.
Conclusion: The existing literature investigating the effect of pre-diagnosis beta blocker use on survival in people with breast cancer is limited. While not all studies found statistically significant findings, the results indicate that pre-diagnosis beta blocker use may result in improved breast cancer survival, but not overall survival. This presentation will discuss potential explanations for these findings, including inadequate adjustment for confounding variables and confounding by indication.