Heart Health After Cancer: A Growing Concern
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Nearly 15 million people are living after a cancer diagnosis in the United States. This number represent over 4 percent of the population, an astonishing figure. And a growing one, as reported last year by the ACS and outlined by the NCI’s Office of Cancer Survivorship.
As cancer patients survive longer they face additional health problems. Radiation to the chest, chemotherapy, antibody therapy and hormone changes can affect blood vessels and heart function in the short term and long, during treatment or years later. But millions affected – and their physicians – remain insufficiently mindful about the risk of heart disease.
It’s the kind of problem a person who’s had cancer, or a doctor who’s prescribed generally helpful treatment, may not want to think about.
Years ago, heart complications of cancer treatment didn’t garner so much attention says, Dr. Javid Moslehi, a cardiologist who leads a program in cardio-oncology at the Vanderbilt University School of Medicine in Nashville, TN. The emerging field involves cardiologists, oncologists, scientists and others who study the long-term effects of cancer treatment on the heart.
“In the past, people were just glad to be alive,” he said. “With so many survivors, there’s a growing need to understand how we can avoid toxic effects of treatment,” he said. “Cardiac issues are becoming central,” he said.
To promote heart health after cancer treatment, Moslehi and collaborators put forth an ABCDE plan that was published last year in Circulation. The “ABCDE” program, developed with a group including Dr. Ann Partridge at Boston’s Dana Farber Cancer Institute, lists pro-active steps a woman with breast cancer might take to prevent or lessen her chances of heart disease.
The ABCDE acronym is a bit more complicated than its five letters might suggest. The gist of the proposed program, published here, is this:
A is for Awareness of the risk of heart disease (and Aspirin, which some might take upon consultation with a doctor);
B is for Blood pressure – which might need monitoring;
B is for Blood pressure – which might need monitoring;
C is for Cholesterol – to keep it low (and Cigarettes – to stop smoking, and your author’s preferred “C”);
D is for Diet – keeping your weight down is good for survival (and for Dose – whether it’s chemo or radiation, how much you get affects risk; and for Diabetes – averting it if possible, controlling it if you have the condition);
E is for Exercise – Do it! (if you’re able; and for Echocardiogram, this images how well the heart is functioning; it’s not a bad way to keep an eye on things if you’re on a drug, like Herceptin among others, that might need be stopped, or the dose adjusted).
The ABCDE take-away is that there are steps a cancer patient might take to deter heart disease. While this initial plan focuses on women who've had breast cancer, the largest cohort of survivors, the principles of preventing or minimizing cardiac problems might help those with other cancer types. Prospective studies are needed.
For the more than 3 million U.S. women who have had breast cancer, the possibility of heart damage from is quite real. Apart from heart disease from chemotherapy drugs and radiation, there may be an augmented risk after early menopause. Natural estrogens, which are deliberately blocked by some types of breast cancer treatment, may be cardio-protective – and were thought to explain why men are more prone to heart disease than women.
February is Heart Health Month. (image adapted, credit: Billie Ward via Flickr)
After breast cancer treatment, women should be mindful of heart disease symptoms, which can be subtle. The unfortunate reality is that many doctors, nurse practitioners and others fail to adequately consider the possibility of vascular and other diseases of the heart when evaluating healthy-seeming and non-elderly women.
So the need for greater awareness of risk applies to physicians, too, especially as patients may move or lose access to their oncologist who knows what they received years or decades earlier. Patients aren’t perfect, either; some “forget” or might not remember if they received radiation 25 years ago after a lumpectomy.
As new drugs become available, the side effects of each treatment, and combinations, should be more carefully weighed. “The FDA is becoming much more focused on cardiovascular safety of cancer drugs,” Moslehi said.
For instance, in October 2013 the FDA pulled back on approval of ponatinib (Iclusig, Ariad Pharmaceuticals), a drug used for treating CML, a chronic form of leukemia. The main reason for the FDA’s switch, which turned yet again after advocates and doctors pushed for continued access to the drug was concern over its vascular toxicity including effects on the heart.
“The CML drug was transiently taken off the market because it wasn’t deemed essential,” Moslehi said. But in some cases of CML, it turns out that ponatinib is the only drug that works. Now the drug is back on the market. But there’s little data on how to avoid its cardiac complications, he noted. Radiation has been a major culprit in accelerating heart disease, Moslehi said.
In recent decades, radiation oncologists have developed methods to protect the heart during treatment. It’s better now than it was in the 1980s and even the 1990s, he suggested. “It may be a greater problem for patients who received radiation a long time ago.”
Old chemotherapy drugs like Adriamycin (the “red devil”) and its chemical relatives are long-known for their capacity to harm a patient’s heart. Years ago, oncologists knew to order serial heart assessments before and after every few cycles of these drugs, to make sure the infusions were doing more good than harm.
The Google-able list of heart toxicity is scary, wide and long, enough to depress almost anyone who’s had treatment. If you look, you’ll find: Recent reports confirm the damaging potential of some of the earliest and most widely-used cancer medications, like 5-fluorourcacil (5-FU). Drugs like taxol can slow the heart and more. Cyclophosphamide delivers its own set of concerns, especially if it’s given at high doses. Herceptin, a drug that has transformed the prognosis (from bad to good) for countless patients, has well-documented cardiac toxicity.
The list goes on, but I’ll stop here. It’s enough to scare the wits out of a reader or person like me who’s trying to move forward with a healthy life after cancer treatment. The ways that cancer drugs cause heart damage are diverse, Moslehi said in an interview with the American College of Cardiology’s CardioSource. Old chemotherapies and radiation are toxic, but so are many newer drugs, he emphasized: angiogenesis inhibitors can cause high blood pressure and clots; tyrosine kinase inhibitors cause vascular disease; one class of agents, called HDAC inhibitors, cause abnormal heart rhythms; other drugs called mTOR inhibitors, lead to metabolic changes that affect the heart.
“It’s complicated,” he told me. “Unfortunately, we have very little idea of what the right assessment before, during and after treatment should be.”
“Anthracyclines are still used for Hodgkin’s, breast cancer and lymphoma. They have lots of cardiac toxicity,” Moslehi told me by phone. “In the past this was not an issue because there were no other therapies to give.”
He and other cardio-oncology investigators are studying the molecular changes that lead to heart problems after cancer. The goal is to find ways to predict and prevent heart disease in people who otherwise benefit from cancer drugs. Ideally the drugs and doses might be selected, or avoided, in each case with information about the patient’s tumor and cardiac risk.
“The whole reason we have this problem in the first place is that the treatments for cancer are so effective, Moslehi said. “The last thing we want to do is take away good treatments.”
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