Toronto—Common cholesterol-lowering drugs show promise for protecting the heard of women undergoing chemotherapy for early-stage breast cancer.

The article in the Journal of the American Heart Association, an open-access journal, describes how statin‐exposed women had a lower risk of hospitalization for heart failure (HF) after early breast-cancer chemotherapy involving anthracyclines. They add that the study showed nonsignificant trends towards lower risk following trastuzumab and suggest their findings support the development of randomized controlled trials of statins for prevention of cardiotoxicity.

“Two types of cancer medications, anthracyclines and trastuzumab, are effective treatments for many women with breast cancer; however, the risk of heart muscle damage has limited their use, particularly in women who are at higher risk for heart problems because of their age or other medical issues,” said lead author Husam Abdel-Qadir, MD, PhD, assistant professor of medicine at the University of Toronto‘s Institute of Health Policy, Management and Evaluation, and a cardiologist at Women‘s College Hospital and the Peter Munk Cardiac Centre, part of the University Health Network in Toronto.

“The mechanisms for these medications are essential to kill breast cancer cells, however; these processes can also damage the cells of the heart muscle, leading to weakening of the heart,” he said.

The exact mechanisms of how statins protect against the cardiac cell damage—which has also been demonstrated in smaller studies—remains unknown, but one theory is that statins have antioxidative and anti-inflammatory actions.

In this case, researchers used linked administrative databases to conduct a retrospective cohort study of women aged 66 years and older without prior HF who received anthracyclines or trastuzumab for newly diagnosed early breast cancer in Ontario between 2007 to 2017.

The study matched statin‐exposed and unexposed women 1:1 using propensity scores, while also matching trastuzumab‐treated women on anthracycline exposure. Overall, the study team matched 666 statin‐discordant pairs of anthracycline‐treated women and 390 pairs of trastuzumab‐treated women (median age, 69 and 71 years, respectively).

Results indicate that the 5‐year cumulative incidence of HF hospital presentations after anthracyclines was 1.2% (95% CI, 0.5%-2.6%) in statin‐exposed women and 2.9% (95% CI, 1.7%-4.6%) in unexposed women (P value, .01). The study also advises that the cause‐specific hazard ratio associated with statins in the anthracycline cohort was 0.45 (95% CI, 0.24-0.85; P value, .01), while, after trastuzumab therapy, the 5‐year cumulative incidence of HF hospital presentations was 2.7% (95% CI, 1.2%-5.2%) in statin‐exposed women and 3.7% (95% CI, 2.0%-6.2%) in unexposed women (P value, .09). The cause‐specific hazard ratio associated with statins in the trastuzumab cohort was 0.46 (95% CI, 0.20-1.07; P value, .07), the study reports.

“Our findings support the idea that statins may be a potential intervention for preventing heart failure in patients receiving chemotherapy with anthracyclines and potentially trastuzumab,” Dr. Abdel-Qadir explained, adding, “This study does not conclusively prove statins are protective. However, this study builds on the body of evidence suggesting that they may have benefits. For women with breast cancer who meet established indications for taking a statin, they should ideally continue taking it throughout their chemotherapy treatment. Women who do not have an indication for a statin should ask their health care team if they can join a clinical trial studying the benefits of statins in protecting against heart muscle damage during chemotherapy. Otherwise, they should focus on measures to optimize their cardiovascular health before, during and after chemotherapy.”

Because the populations are similar in terms of demographics, these results from Canada are likely generalizable to women in the United States but are not necessarily generalizable to younger women or those at lower cardiovascular risk who do not meet indications for being prescribed a statin, the authors point out.

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