Dr Tochi Okwuosa: We Need More Data on Cardio-Toxicity From Radiation

Through her presentations at the American Heart Association’s Scientific Sessions this year, Tochi M. Okwuosa, DO, cardiologist and director of cardio-oncology at Rush University Medical Center—with a research interest in preventive cardio-oncology—addressed important topics related to cardiac and cardiovascular health, as framed by cancer treatment and disease type.

Chief among these were the effects of cancer treatment and cardio-toxicity and the importance of cardiovascular health in cancer survivors. Here she discusses how radiation treatment has evolved to be more precise, thereby reducing risk to the heart, but that much more study and better data on modern radiation techniques are needed because of the underreporting of cardiovascular events in cancer clinical trials.

Transcript

Can you discuss how radiation therapy has evolved and if we understand the true scope of its impact on the heart?

There have been a lot of changes. It used to be that in the 1970s, 80s ,90s, radiation therapy was heavy on the heart in the neck area where you have a lot of the vessels. And that increases the risk of cardiovascular events, increases the risk of heart attacks, strokes, because the carotid arteries were affected and so on. With more recent treatments, with more contemporary radiation treatments, there have been a lot of changes that have reduced the dose to the heart and have increased the specificity, such that when the cancer cell—breast cancer, or lung cancer, esophageal cancer—when they deliver the dose of radiation, they're more specific to those areas and they’ve figured out ways to limit the dose to the heart in a lot of those. So I think that's been very useful.

I think one of the things that really has struck me is the fact that we still don't have very good data for how much modern-day radiation therapy affects the heart. We know that there have been a lot of techniques that are now improved on the dose to the heart, but the question is, “What are the cardiovascular risks now with modern-day radiation therapies?” Do we still have to be concerned?” And I think there was one particular study that looked at the number of radiation therapy clinical trials that are reporting cardiovascular events, and they actually found out that they're minimal. A lot of them are not reporting cardiovascular events, and it's not because the patients that are receiving radiation therapy don't have cardiovascular events. It's just that the people that are conducting the research are just not reporting it—the researchers are not.

We know this because the amount of cardiovascular disease among those who received radiation therapy, the patients that have confirmed cardiovascular disease among those who receive radiation therapy, was actually lower than the general population. And that doesn't make sense, because we know that these people are sick and their risk of cardiovascular disease should be on the higher side—but it was much lower than the general population. So, we know it's been underreported and it's not being reported in some studies at all. That's very concerning. And so that tells me that this is an area that we need to focus on in terms of research and in terms of increasing awareness that the oncology clinical trials need to think about this.