Cholesterol-lowering statins are commonly used to help prevent heart disease. Now a new study hints that they could shield women's hearts from the harms of certain breast cancer drugs.
The study focused on women in Canada who'd been treated with either chemotherapy drugs called anthracyclines or the medication Herceptin. Though the treatments can be lifesaving, they can also damage the heart muscle enough to eventually cause heart failure.
But researchers found that when women were on statins during treatment, they were up to two-thirds less likely to develop heart failure in the years afterward.
The findings do not prove that statins can ward off the side effect, the researchers stressed.
Women on the medications might have had better health care in general or been more "health aware," for example, said lead researcher David Bobrowski, a medical student at the University of Toronto.
"We can't recommend that women go on statins only for this reason," he said.
Only clinical trials, he said, can test whether statins help protect women's hearts during breast cancer treatment.
Bobrowski is scheduled to present his findings at an online meeting of the American College of Cardiology (ACC), March 28-30.
About one-quarter of women with breast cancer receive either anthracyclines or Herceptin, according to the ACC.
Doctors have long known that the treatments can be toxic to heart muscle cells and, in some patients, cause heart failure. Heart failure is a chronic condition in which the weakened heart muscle can no longer pump blood efficiently enough to meet the body's needs — causing problems like fatigue and breathlessness.
Ideally, Bobrowski said, researchers want to limit such heart damage without compromising patients' cancer treatment. Some studies have investigated whether certain blood pressure medications can help, he noted, but have found only modest benefits.
For the current study, researchers analyzed records from nearly 4,000 women age 66 and older who had been treated for early-stage breast cancer with either anthracyclines or Herceptin. Just over 1,500 had been prescribed a statin within a year of starting their cancer therapy.
Overall, those statin users were 58% less likely to develop heart failure after an anthracycline regimen, and 66% less likely to develop it after Herceptin treatment. (The follow-up was over five years for half of the women, and five years or less for the other half.)
The lower risks were seen even after researchers accounted for other factors, such as the women's age, income, health conditions like diabetes and use of high blood pressure medication.
There are reasons to believe statins could shield the heart from cancer drugs, according to cardiologist Dr. Martha Gulati, editor-in-chief of CardioSmart, the ACC's patient education website.
Lab research suggests statins can reduce inflammation and cell death in the heart muscle, for example.
Like Bobrowski, Gulati stressed that the current findings do not prove cause and effect. However, she said, the notion that statins could afford cancer patients some protection is worth pursuing.
"Statins are fairly well-tolerated, they're easy to take, and they're inexpensive," Gulati said. "It would be a simple way to lower heart failure risk."
A trial, called STOP-CA, is already underway, Gulati said. It is testing whether statin treatment can help prevent heart failure in cancer patients undergoing anthracycline treatment. (The drugs are used for many types of cancer.)
Bobrowski said he is not aware of any similar trial of Herceptin patients.
Until clinical trials are done, Gulati said she would not recommend statins solely for the purpose of preventing heart damage from cancer treatment. Even if these findings reflect a benefit of statins, she noted, it's not clear how long the drugs would need to be taken, or at what dose.
For now, Gulati encouraged breast cancer patients to keep their hearts in mind, during and in the years after cancer treatment. That, she said, includes talking with your doctor about your personal risk factors for heart disease, and taking lifestyle measures or any recommended medications to support your heart health.