European and American researchers are reporting that radiation therapy might increase the risk of heart disease in breast cancer survivors.

The researchers arrived at this conclusion after checking the records of nearly 1,000 Danish and Swedish breast cancer patients. All patients had died after developing heart disease following radiation therapy for breast cancer between the period 1958 and 2001.

The study had excluded patients who were taking powerful chemotherapy drugs known to damage the heart. The researchers found that heart disease risk was elevated even in patients who did not have risk factors such as diabetes and heart disease.