Do Cancer Treatments Affect the Heart?

The short answer is yes, said Eugene Storozynsky, M.D., Ph.D., who specializes in heart complications from cancer. He directs the Cardio-Oncology clinic associated with UR Medicine’s Wilmot Cancer Institute — the only such program in upstate New York.

Heart damage (cardiotoxicity) from chemotherapy or radiation therapy is common. And between 5 percent and 15 percent of cancer patients will develop full-blown heart failure after surviving cancer. This number doesn’t account for many others who develop high blood pressure or atrial fibrillation — which increases the risk of stroke — as a result of cancer treatment.

Research led by Rochester, which included patients at 12 cardio-oncology programs across the U.S., showed that a pacemaker-like device can help normalize heart damage in cancer survivors. The study results are reported in the Journal of the American Medical Association (JAMA).

How do chemo and radiation damage the heart?

• Some types of chemotherapy (primarily in a class of drugs called anthracyclines) weaken the heart muscle from a buildup of calcium and other chemical reactions in the body that release harmful free radicals. Thus, chemotherapy side effects include cardiomyopathy (an enlargement) or congestive heart failure. However, chemotherapy does not increase the risk of heart attack, Storozynsky said, because chemotherapy usually does not impact blood flow to the arteries.
• Radiation therapy aimed at the chest region for breast cancer or lung cancer, for example, can prompt a thickening of the blood vessels and heart valves, inflammation, and artery blockages. Heart problems due to radiation often impact younger people, too.

Heart disease can appear during cancer treatment — or emerge as long as 15 to 20 years later, Storozynsky said.

“I always emphasize prevention to my patients who are cancer survivors,” he said. “You do not want to be told you’re cancer-free, only to develop congestive heart failure or die of another type of preventable heart problem. The best thing a person can do is maintain a healthy lifestyle and get the proper follow-up with a cardiologist.”

Prevention includes regular exercise, a diet rich in fruits and vegetables, and medications that lower blood pressure and/or cholesterol.

Some studies have shown that cancer patients who are already on a statin drug when they receive chemotherapy have a lower incidence of heart failure, compared to people who do not take statins. However, research has not confirmed that statins are fully protective, Storozynsky said.

Who is at greatest risk of heart problems from cancer treatment?

Women seem to be most at risk; physicians are not sure why. Women with breast cancer who receive targeted therapies for the HER2-positive subtype, for example, have a 30 percent chance of developing heart failure during treatment.