Brest cancer increased risk of Heart Disease

Breast cancer patients who undergo radiation therapy have a slightly increased risk of ischemic heart disease within five years, and the risk persists for at least twenty years, researchers from Oxford University, England, the Karolinska Institute, Sweden, and Copenhagen University Hospital, Denmark, reported in NEJM (New England Journal of Medicine).
The authors added that the risk of developing ischemic heart disease and/or dying prematurely from heart disease is more closely linked to those with other heart disease factors, including diabetes, obesity, and smoking when radiation therapy was administered.

Ischemic (British spelling: ischaemic) heart disease is characterized by ischemia of the heart muscle - ischemia is the restri

ction in the blood supply to tissue. In most cases, ischemic heart disease is caused by coronary artery disease. Overall, in the general population, it is more common among men, people with close relatives with ischemic heart disease, regular smokers, individuals who have high cholesterollevels, diabetes, and/or hypertension (high blood pressure). Ischemic heart disease is also known as myocardial ischemia.

Doctors have always presumed that women with breast cancer who undergo radiation therapy have a higher risk of heart disease later on. However, not much was known about the specifics of the risk and whether susceptibility to ionizing radiation might affect some patients more than others.

In this study, the scientists set out to determine what impact radiotherapy (and its doses) might have on heart disease risk among women who were treated for breast cancer.

The study involved 2,200 female patients who had been administered radiation therapy for breast cancer from 1958 to 2001. The researchers used data from radiotherapy charts and medical records to estimate the mean radiation dosage to the heart. They also gathered and examined data regarding each woman's heart disease risk factors as well as their medical histories.

Radiation dosage influences heart disease risk

The team found a clear association between the radiation dose and ischemic heart disease later in life. Although the risk is real, the authors stressed that it is still small.

A higher risk of heart disease among women receiving radiation therapy for breast cancer was more evident among those with:

• angina
• other heart diseases
• chronic obstructive lung disorder
• diabetes
• obesity
• a short distance between the chest wall and the heart
• and women who smoked

The risk peaked during the first ten years after radiation therapy, and then dropped, but remained higher-than-normal for at least twenty years.

Radiation for breast cancer treatment and heart risk link studied for 40 years

Two scientists published an article in Lab Investigation in 1971 stating that radiation to the breast could damage the capillaries and restrict blood flow to the heart. Over the last 40 years studies have come up with contradictory findings. Another study published in the International Journal of Radiation Oncology/Biology/Physics (May 2007) found that older breast cancer patients with early stage disease who undergo radiation therapy have no increased risk of a heart attack. They added that "Interestingly, pre-existing cardiac risk factors such as diabetes,hypertension and hyperlipidemia do not potentiate the effects of radiation on the heart."