‘Double-Edged Sword’: Lung Cancer Radiation Rx May Raise Heart Attack Risk

Radiation treatment for lung cancer can help extend lives, but it might also raise a patient’s odds for heart attacks and heart failure, a new study shows.

Many patients may have no choice but to accept the risk: For about half of people diagnosed with the number one cancer killer, radiation remains the only viable treatment, the research team noted.

“This is alarming data — to think that one in 10 of the patients I’m treating for this type of cancer will go on to have a heart attack or other major cardiac event,” senior author Dr. Raymond Mak, a thoracic radiation oncologist at the Brigham and Woman’s Hospital in Boston, said in a hospital news release.

“These cardiac events are happening earlier and more often than previously thought,” he added. “More patients are living long enough to experience this risk of cardiac toxicity. We need to start paying attention to this and working together with cardiologists to help these patients.”

One expert unconnected to the study agreed that patients face heart risks, but in many cases it’s tough to tease out why.

“Although the radiation that we give to patients for lung cancer is of course directed mainly at their tumor, there may be overlap in the beams of radiation that affect the heart,” explained Dr. Adam Lackey. He directs thoracic surgery at Staten Island University Hospital in New York City.

But, “since smoking remains the most potent risk for lung cancer, and smoking also is a risk factor for heart disease, many lung cancer patients have a diagnosis of or are at risk for heart disease, as well,” he noted.

In the new study, Mak and his colleagues looked at data on 748 lung cancer patients who were treated with radiation therapy. After treatment, about 10% of the patients did go on to have a heart attack or heart failure, where the heart’s pumping efficiency is compromised.

While the study couldn’t prove cause and effect, Mak’s team found that the higher the radiation dose, the greater the risk of having a heart problem. The rate of cardiovascular events was especially high for people who didn’t have heart problems before their treatment, the investigators noted.

What to do? Mak’s group believes that using the lowest possible dose of radiation is the best course to take.

“When possible, we should be thinking about ways to minimize cardiac radiation dose,” Mak said. “Recognizing that we may not always be able to do that, we’re now collaborating with our cardiology colleagues to explore early interventions to help mitigate the effects of cardiac injury from radiation therapy.”

Dr. Len Horovitz is a pulmonary specialist at Lenox Hill Hospital in New York City. Reading over the findings, he agreed that radiation therapy for lung cancer is one of medicine’s “double-edged swords.”

“While the mechanism of damage is unclear, it is apparent that embarking on a course of radiation for lung cancer may cause cardiac damage,” Horovitz said.

For his part, Lackey agreed that, “as we have pushed the limits of what types of radiation — and how strong of a dose we give patients who have lung cancer — it is important to recognize the long-term effects that this radiation may have for lung cancer survivors.”

The report was published June 10 in the Journal of the American College of Cardiology.

More information

The American Cancer Society has more about lung cancer.