Written by Todd Neff on behalf of National Jewish Health
The war on cancer has been ongoing for more than a half century now. While the battles continue, there has been great progress. Cancer gets spotted earlier. Cancer treatments are constantly improving. As a result, cancer patients are living longer, better lives with the disease in check.
But along with the new treatments has come an increasingly common health problem called cardiotoxicity. That’s an umbrella term for damage to the heart and cardiovascular system caused by – or made worse by – cancer treatments.
Cardiotoxicity can cause myocarditis (heart inflammation), high blood pressure, abnormal heart rhythms or heart failure. Symptoms can appear during or soon after cancer treatment – or years afterward.
National Jewish Health cardio-oncologist Christopher Fine, MD, FACC, says cardiotoxicity predates the war on cancer. For years, children treated with high doses of still-common anthracycline chemotherapies ended up with heart failure. But, in general, the short lifespan of cancer patients hid the reality of cardiotoxicity.
“We never had the opportunity to see these adverse cardiovascular effects,” said Dr. Fine. “Now that cancer-related deaths have significantly decreased, we’re kind of exchanging that for something else – and the vast majority of time, it ends up being a cardiovascular cause.”
Cancer Treatments Can Triggers Heart Issues
Cancer treatments can both trigger cardiotoxicity and make it worse. When it comes to cancer treatments, all carry cardiovascular risks.
Anthracyclines – doxorubicin being a prime example – have no known safe dose. The effects of this type of medicine are cumulative. “So the more you get, the higher the potential of cardiotoxicity, even if you’ve had it in the remote past as a child,” said Dr. Fine.
Herceptin (trastuzumab), a common treatment for HER2-positive breast cancer, can weaken the heart and even cause heart failure. Immunotherapies also can harm the heart. It is estimated that cardiotoxicity-related myocarditis happens in about 1% of cancer patients who receive immune checkpoint inhibitors in their treatments. Heart attacks and strokes resulting from that inflammation cause the deaths of about half of those patients.
Cardiotoxicity risk has tracked with what Dr. Fine describes as “an explosion” in the use of immune checkpoint inhibitors in cancer care.
“They used to be second-, third-, or fourth-line treatments for a very few cancers like certain types of lung cancer and metastatic melanoma,” he said. “Now they’re often first- and second-line treatments for most, if not all, types of cancers.”
These examples of cancer therapies are not alone in impacting the heart, arteries and veins. Many cancer treatments are known to increase blood pressure, cholesterol, blood sugar and body weight. All contribute to overall heart disease risk. Cancer patients on blood thinners that increase the risk of bleeding or platelet agents that increase the risk of clotting, can complicate care and boost the risk of heart attacks, strokes and heart failure.
Cancer Treatments Can Be Hard on the Heart
Cancer treatment also can lead to behaviors that are hard on the heart. Breast cancer is one example. In a scientific statement on the intersection of breast cancer and heart disease, The American Heart Association said patients who have had cancer and are in remission are at higher risk of cardiovascular problems. Also, major risk factors for breast cancer and heart disease overlap: age, tobacco use, obesity and a sedentary lifestyle, among them.
“When a woman is diagnosed with breast cancer, her adherence to treatments for other health conditions also goes down, such as the management of cholesterol or keeping diabetes under control,” the authors wrote.
Get Cardio-Oncology Care Early
Cardiotoxicity is a concern for those undergoing or who have been through cancer treatment. Cardio-oncology is a young field with a growing number of specialists such as Dr. Fine. They have developed ways to screen, diagnose and treat cardiotoxicity so patients’ cancer care can proceed as planned.
Given the nature of cardiotoxicity, it’s never too late to see a cardio-oncologist. But the earlier, the better, said Dr. Fine.
“Ideally, I would see the patient at the time the cancer is diagnosed, before treatment has started.”
Seeing a Cardiologist for Cardiotoxicity
What is Cardiotoxicity?