Risk of Heart Disease From Breast Cancer Radiation Declines

Radiation exposure from breast cancer treatment is associated with a small risk of heart disease later in life, but the risk is now lower than it was 20 years ago, says a new study by radiological researchers at Columbia University Medical Center.

The chance of a woman's developing heart disease induced by her radiation treatment varies by her underlying risk of heart disease, the researchers also found.

The findings, which were published Oct. 28 in JAMA Internal Medicine, apply only to women undergoing radiation treatment for cancer in the left breast, which is closer to the heart.

“On average, the risk of developing serious heart disease from radiation exposure during breast cancer treatment today is less than 1 percent, about 1 in 300. It’s a risk, but not a huge risk,” says the study’s lead author, David J. Brenner, PhD, director of the Center for Radiological Research and Higgins Professor of Radiation Biophysics at Columbia University College of Physicians & Surgeons.

“For someone who already has a high risk of developing heart disease, the radiation-related cardiac risk may be as high as 1 in 30, but for someone with low underlying risk the radiation risk may be as low as 1 in 3000, which is absolutely miniscule.”

Women should not forgo radiation treatment because of the small risk of developing heart disease in the future, Brenner warns. “Lumpectomy plus radiation is a superb treatment for early stage breast cancer,” he says. “Nothing we have found in any way contradicts that.”

Breast cancer patients with a high underlying risk of heart disease can reduce their risk of radiation-induced disease with the same methods that reduce risk in general: exercise, diet, smoking cessation, and medication if necessary.

Changes in radiation treatment that lower the dose to the heart may also reduce heart disease risk for patients in the future. Such changes are currently under investigation.