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WASHINGTON - Women treated with radiation for breast cancer during the 1980s may have a higher risk of heart disease, researchers in the Netherlands reported today.
Smokers have an especially high risk, as do patients who got surgery, radiation and chemotherapy for their breast cancer, the researchers said.
Their study, published in the Journal of the National Cancer Institute, confirmed that women treated in the 1970s had a higher risk of heart disease. But no one had conclusively determined the risk for women treated in the 1980s using improved techniques, they said.
Their study did not look at women treated after 1986.Radiation techniques have become increasingly precise since then.
Dr Maartje Hooning of the Netherlands Cancer Institute in Amsterdam and colleagues studied 4414 10-year survivors of breast cancer treated between 1970 and 1986. Nearly a third of the women were followed for 20 years.
They found a 40 per cent increased risk of heart disease among those treated up to 1980, and a 35 per cent increased risk in those treated after 1980, although they said the 35 per cent was not statistically significant -- which means it may be unreliable because of a lack of information.
Women who smoked and had radiotherapy had triple the risk of a heart attack, they said -- a surprising finding that means women should be strongly advised to quit smoking at the time of treatment. They said 10 per cent of the smokers continued smoking after treatment.
"Patients who underwent radiotherapy plus adjuvant chemotherapy (cyclophosphamide, methotrexate, and fluorouracil) after 1979 had a higher risk of congestive heart failure than patients who were treated with radiotherapy only," they wrote.
"Radiotherapy as administered from the 1980s onward is associated with an increased risk of cardiovascular disease," the researchers concluded.
The women who received only surgery, without chemo or radiation therapy, had a lower risk of heart attack than the general female population, the researchers found. They said women may take up a healthier lifestyle after a diagnosis of breast cancer.
- REUTERS
