Supplementary Material for: The risk of cardiovascular disease following aromatase inhibitor therapy for breast cancer in postmenopausal women: a systematic review and meta-analysis

Background
More women are recovering and living longer lives due to advancement in breast cancer therapies. Aromatase inhibitors (AI) are one form of endocrine therapy for breast cancer that may have an impact on the risk of developing cardiovascular diseases later in life. This study investigated whether aromatase inhibitors therapy for breast cancer in postmenopausal women increase the risk of developing cardiovascular disease in comparison with tamoxifen therapy or no hormonal therapy.
Methods
Comparisons were made between tamoxifen and no hormonal therapy. We searched publicly available databases for studies including postmenopausal women who underwent AI therapy for breast cancer investigating the risk ratio of specific cardiovascular outcomes and cardiovascular death.
Results
There was a significant increase in the risk of ischaemic heart disease (RR 1.59, 95% CI: 1.25-2.02, p<0.05), myocardial infarction (RR 1.50, 95% CI: 1.13-1.99, p<0.05), heart failure (RR 1.63, 95% CI: 1.14-2.32, p<0.05) and other cardiovascular events (RR 1.26, 95% CI: 1.12-1.40, p<0.05) in the AI group when compared to tamoxifen. However, there was a significant decrease in the risk of myocardial infarction (RR 0.77, 95% CI: 0.65-0.90, p<0.05) in the AI group when compared to no hormonal treatment.
Conclusion
There is an increased risk of cardiovascular disease for AI therapy in comparison to tamoxifen therapy, but the risk is not elevated when compared to those receiving no hormonal treatment.
Implications for Cancer Survivors
Prognosis and survival of patients should be an important consideration in choosing between tamoxifen and AI therapy among patients receiving treatment for breast cancer.