The role of cardio-protective agents in cardio-preservation in breast cancer patients receiving Anthracyclines ± Trastuzumab: a Meta-analysis of clinical studies

Background: Breast cancer patients often receive cardiotoxic drugs such as anthracyclines (ANT) and Trastuzumab. Numerous trials have tested angiotensin converting enzyme inhibitors (ACEi), angiotensin receptor blockers (ARB), and beta-blockers (BB) as monotherapy or in combination to reprogram cardiac function dynamics in these patients, but no clear conclusions have been reached thus far, due to evident heterogeneity in the design of clinical studies. Methods: This PRISMA-guided systematic review and meta-analysis assessed a pooled effect estimate of the potential benefit/harm of ACEi/ARB/BB in breast cancer patients treated with ANT ± Trastuzumab. The protocol was registered on the PROSPERO database. Electronic databases (PubMed, Cochrane Central, Scopus, Web of Science) were searched from inception until February 2019. Results: Twenty-two prospective studies comprising of 2,302 participants were included in the meta-analysis. The 16 studies testing the protective effects of ACEi/ARB/BB after immediate completion of chemotherapy showed a significant lower difference in the mean change of left ventricular ejection fraction (LVEF) in patiens receiving cardio-protective drugs as compared to controls, with a standardized mean difference [SMD = -2.36 (95% CI: -3.23 to -1.49), p < 0.00001] favoring the protective role of these drugs. LVEF was evaluated after 6 months after completion of chemotherapy in 3 studies, where ACEi/ARB/BB persistently showed cardio-protective effects as compared to controls [SMD = -6.54 (95% CI: -10.74 to -2.34), p = 0.002]. After 1 year from completion of chemotherapy, ACEi/ARB/BB preserved beneficial effects on LVEF vs control [SMD = -5.37 (95% CI: -9.31 to -1.43), p = 0.008]. The effect of ACEi/ARB/BB on end-systolic volume (ESV) and end-diastolic volume (EDV) were evaluated immediately after chemotherapy completion and after 1 year. No significant protective effect was apparent. On the other hand, end-diastolic diameter (EDD) was significantly spared in the ACEi/ARB/BB group vs control after chemotherapy completion [SMD = -1.11 (95% CI: -1.88 to -0.35), p = 0.004]. Heart failure as a clinical endpoint was assessed in 11 trials. The incidence of heart failure was significantly lower in the ACEi/ARB/BB group as compared to control [Odds ratio = 0.12 (95% CI: 0.03 to 0.45), p = 0.002]. Conclusion: ACEi/ARB/BB may act as cardioprotective agents in breast cancer patients who undergo ANT ± Trastuzumab. More studies are required to better assess the magnitude of the cardiotoxicity hazards of ANT ± Trastuzumab, with more precise assessment of the effect of ACEi/ARB/BB on cardio-protection.