Breast cancer and radiation: Cardiac risk, yes, but a small one

November 5, 2013 | by

Radiation therapy for breast cancer has undergone dramatic improvements over the years, increasing survival and reducing the risk of recurrence. But new research suggests that this form of treatment can increase cardiac risk in early-stage breast cancer patients.

Tumor in breast

Radiation for breast cancer can increase the risk of heart disease, a new study finds. A City of Hope physician adds some perspective to the findings.

The findings, published by researchers from Columbia University Medical Center as a research letter in the journal JAMA Internal Medicine, seem alarming. They're based on radiation treatment plans in 48 women who had early-stage breast cancer at New York’s University’s department of radiation oncology.

One City of Hope surgeon, however, cautions against overreacting. When used for the treatment of breast cancer, radiation therapy is a highly effective way to destroy cancer cells in the breast that may linger after surgery, said Laura Kruper, M.D., head of breast surgery service at City of Hope and director of the Rita Cooper Finkel and J. William Finkel Women's Health Center.

“There are newer radiation therapy methods that reduce the risk,” Kruper said in a recent interview with HealthDay. "We are really tailoring patients' treatments. We have a lot of tools now where we can offer women breast conservation and minimize their [heart] risk."

Further, the risk found by Columbia researchers was small, with the lifetime risk of a major coronary event ranging from 0.05 percent to 3.5 percent, depending on how the radiation was administered and the patient’s overall risk for heart disease.

Women at greatest risk of heart disease were the ones who received radiation treatment on their left breast while lying face down and who were already at risk of heart disease. Women at the lowest risk were those who received treatment on their right breast while lying face down.

Researchers noted that for a majority of the women they studied, the “absolute risk of ischemic heart disease from breast cancer radiotherapy is likely to be small compared with the likely absolute benefit from radiotherapy.”

Kruper suggested the findings should be considered as part of a larger treatment picture, telling Reuters Health that she sees "a lot of women with early breast cancer who would be great candidates for breast conservation but they are afraid of the radiation risks to the heart." She added that the data was actually reassuring, because "the cardiac risks aren't excessively high."

She added that many women with early-stage breast cancer "are opting to have a much bigger procedure like mastectomy to avoid radiation when really modern radiation is not that bad. ... If some women are on the fence or hesitating about radiation, I will send them to our radiation oncologist for a discussion beforehand.”

City of Hope even offers intraoperative radiation therapy (IORT), which delivers a dose of radiation in a single treatment session, while  preserving more healthy tissue and minimizing radiation to other organs.

"I have a breast cancer patient who has a mitral valve repair and is on Coumadin, and she has a pacemaker on the left side and her cancer is on the left and she is not a great candidate for mastectomy,” Kruper told Reuters Health. “This is a person that I would recommend IORT because it will minimize any scatter to the pacemaker and any damage to the heart; it's a great tool to have," she said.

As always, treatment decisions should be based on the individual.