Effect Of Prophylactic Betablocker On Anthracycline Induced Cardiotoxicity

Objective: Cancer outcomes continue to improve due to earlier detection and newer targeted therapies.Even in this ecouraging context,anthracycline is still widely used in many cancer treatment,as a prominent role.As a consequence of the growing number of cancer survivors,the incidence of anthracycline induced cardiotoxicity is increasing.However,the optimal primary preventive strategy is lacking.So we conducted this metaanalysis of all randomized controlled trials to evaluate the efficacy of beta blockers for the primary prevention of anthracycline-induced cardiotoxicity.Methods: We do a comprehensive research of Pubmed,Embase and Cochrane Library.Only RCTs in human subjects published in English were considered.Articles published until June 2018 were eligible for inclusion.Adult patients were all diagnosed with cancer and took beta blockers before accepted anthracycline based treatment.We used the Cochrane quality assessment tool for quality assessment of articles and risk of bias.The primary endpoint of the analysis was low-ejection fraction events(LVEF<50%),and the odds ratio(OR value)was selected as the statistical value of the efficacy analysis.The secondary endpoint was the change of left ventricular ejection fraction in patients from the initiation of therapy to the end of the study,the weighted mean difference was used as the statistical measure,and the 95% confidence interval(95%CI)was used for all effect sizes.Studies that included anthracyclines alone but not herceptin were independently analyzed.Results: A total of 10 RCTs were included,including 794 patients.The results showed that anthracycline±herceptin combined with beta blocker reduced the incidence of low ejection fraction events [2.7% vs.5.2%,OR: 0.38,95%CI:(0.18,0.85);p=0.02;I2=0%] and the reduction of ejection fraction [MD: 2.29%;95%CI:(0.16-4.41);p=0.04;I2=85%].When chemotherapy regimens included anthracyclines alone,beta blockers also reduced the incidence of low ejection events [2.9% vs 5.7%,OR: 0.38,95%CI:(0.18,0.85);p=0.02;I2=0%] and maintained ejection fraction.[MD: 2.57%;95%CI:(0.21-4.93);p=0.03;I2=87%] And the evidence of this protective effect is more sufficient in carvedilol which has antioxidant effect.Conclusion:Prophylactic use of beta blockers in anthracycline chemotherapy maintained ejection fraction and reduced the incidence of early left heart dysfunction,and the benefit of antioxidant beta blockers-carvedilol was more pronounced.Further investigation is warranted regarding the protective effect of beta blockers on cardiac structures,the type of ? blockers and the duration of use.