Radiotherapy is effective in reducing recurrences of
breast cancer. However, the radiation has been associated with increased
incidence of heart disease, which may also result in death in some cases. A
study published in the New England
Journal of Medicine
studied some of the factors that could increase this
The study was conducted in Sweden and Denmark on
women who received radiation treatment for advanced breast cancer. The number
of women who suffered heart attack or died due to a heart attack, or had to
undergo procedures like angioplasty was recorded.
The researchers found that the time interval for the
development of heart disease following breast cancer varied among different
women. Around 44% instances of heart disease were detected less than 10 years
after the cancer was diagnosed, 33% occurred between 10 and 19 years, and 23%
occurred 20 or more years later.
received radiation to the left breast had more chances of heart disease as
compared to women who received radiation to the right breast
. Since the heart is on the
left side of the chest, it was more exposed to the radiation directed to the
left breast. The chances of heart
disease was also more common in women with other health conditions like
circulatory diseases, diabetes, lung disease, increased weight, as well as
those who smoked or took regular painkillers
finding of the study was that the rate of heart disease increased with
increasing dose of radiation
. This increase was estimated at 7.4% per gray.
The researchers also found that the risk of heart
disease increased within the first 5 years of radiation and continued for at
least 20 years.
The study thus indicates that women receiving
radiation therapy are at a higher risk of developing cardiac events like heart
attack. The risk is higher with higher doses and in women at prior risk of
heart disease. This should be taken into consideration in women undergoing
radiation therapy for breast cancer and the benefits of the treatment in
preventing recurrence of the cancer should be weighed against the risk of
developing heart disease.
Risk of Ischemic Heart Disease in Women after Radiotherapy for Breast
Cancer; Sarah Darby et al; N Engl J Med 2013; 368:987-998.