Protecting Heart Health During, After Cancer Treatment and Into Survivorship

As cancer survivors have an increased risk for heart disease compared with people who have never been diagnosed with cancer, it remains important to keep cardiovascular health in mind throughout one’s cancer journey, an expert said.

“Heart disease is a leading cause of death among people who have been diagnosed with cancer,” said Dr. Wendy Bottinor, assistant professor of cardiology at Virginia Commonwealth University in Richmond, in an interview with CURE®. “And that risk is not just during the acute period when people are undergoing cancer therapy. It actually carries forward into long-term survivorship.”

Several factors may play into this increased risk for heart disease including the types of therapies a patient received during treatment and the doses they were administered at. CURE® spoke with Bottinor to learn more about how cancer treatment may impact a patient’s risk for heart disease and what can be done to potentially control this risk.

How can treatments like chemotherapy and radiation alter the structure of the heart?

There's even more to it than that. Cancer itself, we think, can cause negative effects on heart health. There's evidence that women who are diagnosed with breast cancer can't exercise as well as women who are of a similar age and health status but don't have cancer. And that's even before folks have received any cancer therapy, so we don't fully understand all of the nuances of the connections. But we do know that cancer and heart health are very closely linked, and that cancer can negatively impact heart health.

The way that cancer therapies negatively affect the heart really depends on what therapy someone's receiving. It's not universal. For example, one of the more classic chemotherapies that we think of are the anthracycline chemotherapies. We think that therapy affects the heart through a couple of different ways. One is that we think it can poison the mitochondria, which are the energy-producing structures within heart cells. We also know that it can lead to death of heart cells and also increased scar tissue within the heart.

For radiation therapy, when looking at mechanisms of how that adversely affects the heart, there's also a risk for scar tissue formation. But there's also risks for radiation therapy to cause blockages in heart arteries. And so that can be a mechanism by which it creates heart dysfunction.

Radiation therapy can also cause issues with heart valves, where they either become leaky or too tight and don't allow blood to flow through the heart properly. That's also heart disease, but it's a different mechanism for how those agents have caused it.

Can cancer treatment also lead to cardiac events like heart attack and stroke?

If we want to go back to the example of radiation therapy, so if there's blockages in the heart arteries, that definitely can put people at risk for heart attack. And so actually depending on the situation, periodic stress testing is sometimes recommended, so that we can be really proactive about looking for any of these blockages. And if there is anything that we find, going ahead and treating them before someone actually develops a heart attack.

Some of the therapies that are used for more of the hematologic malignancies like leukemias, for some of them, there's oral pills that people take every day, and certain classes of those medications increase the risk for blood clots. And we also think that sometimes these medications increase the risk for cholesterol depositing in in arteries.

Why may patients with cancer not think about undergoing some type of heart screening?

I don't think it's that patients think they're not eligible. I think it's that they don't even realize that screening is a part of standard of care for many survivors, and there's a lot of different reasons for that.

I think part of it is that oncologists are focused on treating cancer, and that is their area of expertise. And so when it comes to survivorship, oftentimes people are better served if there is a multidisciplinary team involved that can think about not just the cancer, making sure that the person is cured and there's no evidence of recurrence, but think about the person head to toe and what are the potential implications of cancer therapy.

What advice would you give to patients?

We know that for anybody, high blood pressure is a bad thing. It increases the risk for heart attack and stroke. But we know that actually among people who have received cancer therapies, hypertension is a really bad actor.

An example I'll give my patients is let's say that high blood pressure increases your risk for heart disease by two, and having received cancer therapy increases your risk for heart disease by two. It would naturally make sense that if you have both of those factors, your risk is increased by four. But there's actually some adverse synergistic process between things like high blood pressure and previous cancer therapies. And so for many individuals, that risk is more like 40. It's not additive; it's exponential.

The things that I always am looking for are opportunities to be proactive about protecting heart health. And that means that blood pressure should be really well controlled for our cancer survivors. And I do ask people to consider monitoring their blood pressure at home — particularly younger survivors — because we know that typically things like high blood pressure will start about 10 years earlier in our survivors than it does in the general population. So there are a lot of young folks who think that they don't need to worry about checking their blood pressure yet because they just haven't reached that age range where you would expect high blood pressure to develop.

Something we can do is promote awareness about things like checking your blood pressure at a local pharmacy or, if you can get a machine, periodically checking at home and being open to the idea that blood pressure medicines, cholesterol medicines, things like that are resources to help us be very proactive about protecting heart health and preventing any more serious heart-related conditions from developing in the future.

Beyond taking blood pressure measurements, is there anything else that patients should be mindful of that they should bring up to their care team?

There are certain items that patients may want to bring up with their health care team, explained Dr. Wendy Bottinor.

Our goal is to catch any signs of heart disease at their earliest stages possible because we think that gives us the best opportunity to treat and have a beneficial outcome for our patients. It's important that people try to be mindful of things like, do they have any new swelling in their legs or their belly that they never had before? Are they having significant shortness of breath either when they're at rest or when they're up trying to exercise? Are they severely fatigued compared to how they normally feel? Those aren't necessarily specific signs, but I think those are things that any provider who's taking care of a cancer survivor would want to know about, so that they can try to help understand why that survivor is feeling that way, and figure out how to make that better as quickly as possible.

This transcription has been edited for clarity and conciseness.

For more news on cancer updates, research and education, don’t forget to subscribe to CURE®’s newsletters here.