Breast cancer radiation boosts heart disease risk

Wednesday, March 20, 2013 by: Jonathan Benson, staff writer
Tags: breast cancer, radiation, heart disease

(NaturalNews) Women who undergo radiation treatments for breast cancer could be putting themselves at serious risk of developing heart disease later in life, according to a new study published in the New England Journal of Medicine (NEJM). Researchers from the U.K. found that for each gray (Gy) unit of radiation administered that impacts the heart, a woman's risk of having a major cardiovascular event at some point in the future increases by about 7.4 percent.

Based on an analysis of 2,168 breast cancer survivors from Sweden and Denmark dating back to 1958, Sarah Darby from the Clinical Trial Service Unit at Oxford University in England and her colleagues learned that radiation given for breast cancer treatment is directly correlated with an increased risk of major coronary events. As it turns out, breast cancer survivors with the highest radiation exposures also had the highest rates of heart disease.

According to the figures, the average dose of radiation to the heart among women with left breast tumors was 6.6 Gy, while those with right breast tumors had a 2.9 Gy average. Overall, this amounts to radiation doses of 4.9 Gy among all women. After adjusting for countries of residence, age at diagnosis and year of diagnosis, researchers determined that the average woman treated for breast cancer is about 16.3 percent more likely than the average woman to have a major cardiac event in the first five years after exposure.

After five years, that percentage dropped slightly to 15.5 percent, and in the following 10 years dropped to 1.2 percent. But after the first 20 years following radiation exposure, breast cancer survivors were still found to have an 8.2 percent elevated risk of developing myocardial infarction, coronary revascularization, or dying from ischemic heart disease.

"Clinicians may wish to consider cardiac dose and cardiac risk factors as well as tumor control when making decisions about the use of radiotherapy for breast cancer," concluded the study's researchers, noting that women with preexisting cardiac risk factors have an even highest absolute risk of developing serious cardiovascular complications.

Cardiovascular risk just 'tip of the iceberg' for radiation side effects

Although some in the medical field were quick to dismiss the findings as overblown and not as serious as they seem to appear, others affirmed them as both valid and ominous. In fact, one prominent doctor admits the findings may very likely just be the "tip of the iceberg" when it comes to the long-term health consequences of radiation treatment.

"In addition to ischemic cardiac disease, radiation therapy has been associated with other cardiac conditions, including pericardial disease, peripheral vascular disease, cardiomyopathy, valvular dysfunction, and arrhythmias," said Dr. Javid Moslehi of Brigham and Women's Hospital in Boston to ABC News about the apparent dangers of radiation treatment for breast cancer.

Sources for this article include:

http://www.mnn.com

http://abcnews.go.com

http://www.cbsnews.com