Long-term effectiveness of empiric cardio-protection in patients receiving cardiotoxic chemotherapies: A systematic review & bayesian network meta-analysis

Background: Cardioprotective therapies represent an important avenue to reduce treatment-limiting cardiotoxicities in patients receiving chemotherapy. However, the optimal duration, strategy and long-term efficacy of empiric cardio-protection remains unknown. Methods: Leveraging the MEDLINE/Pubmed, CENTRAL and clinicaltrials.gov databases, we identified all randomised controlled trials investigating cardioprotective therapies from inception to November 2021 (PROSPERO-ID:CRD42021265006). Cardioprotective classes included ACEIs, ARBs, Beta-blockers, dexrazoxane (DEX), statins and mineralocorticoid receptor antagonists. The primary end-point was new-onset heart failure (HF). Secondary outcomes were the mean difference in left ventricular ejection fraction (LVEF) change, hypotension and all-cause mortality. Network meta-analyses were used to assess the cardioprotective effects of each therapy to deduce the most effective therapies. Both analyses were performed using a Bayesian random effects model to estimate risk ratios (RR) and 95% credible intervals (95% CrI). Results: Overall, from 726 articles, 39 trials evaluating 5931 participants (38.0 ± 19.1 years, 72.0% females) were identified. The use of any cardioprotective strategy associated with reduction in new-onset HF (RR:0.32; 95% CrI:0.19–0.55), improved LVEF (mean difference: 3.92%; 95% CrI:2.81–5.07), increased hypotension (RR:3.27; 95% CrI:1.38–9.87) and no difference in mortality. Based on control arms, the number-needed-to-treat for ‘any’ cardioprotective therapy to prevent one incident HF event was 45, including a number-needed-to-treat of 21 with ≥1 year of therapy. Dexrazoxane was most effective at HF prevention (Surface Under the Cumulative Ranking curve: 81.47%), and mineralocorticoid receptor antagonists were most effective at preserving LVEF (Surface Under the Cumulative Ranking curve: 99.22%). Conclusion: Cardiotoxicity remains a challenge for patients requiring anticancer therapies. The initiation of extended duration cardioprotection reduces incident HF. Additional head-to-head trials are needed.