Chest radiation boosts death risk from heart disease

Feb 4 is the National Wear Red Day, which is an annual event organized by American Heart Association and government agencies to raise awareness about heart disease in women.  February is the American Heart Month, according to the Centers for Disease Control and Prevention.

CDC says on its website heart disease is the number one killer of women.  And it recommends that women should exercise 2.5 hours per week, eat a healthy diet, which limit foods and drinks high in calories, sugar, salt, fat and alcohol, and avoid smoking and second hand smoke.

For women who are at risk for heart disease, attention should be paid to the signs or symptoms of heart attack, which include pain or discomfort in the jaw, neck, or back, fatigues, feeling week, light-headed, nauseated or dizzy, having pain or discomfort in the chest, arms, or shoulder or upper body, having shortness of breath or experiencing a cold sweet.

One thing rarely publicized is that radiation therapy indicated to treat breast cancer can drastically boost risk of death from heart disease.

A study published in the Jan 25, 2011 issue of the Journal of the American College of Cardiology found that women receiving chest radiation faced a up to 76 percent increased risk of dying from heart disease in a period of 28 years, compared with those untreated.

Radiation has been known to boost risk of cancer, and there is no safe threshold, meaning any dose of it can lead to DNA damage and increase the risk.  But the fact that radiation can also cause vascular damage leading to heart disease and stroke has not been well publicized.

Dr. Kim Bouillon of the Gustave Roussy Institute in France followed 4,456 women who were diagnosed and treated for breast cancer at the institute between 1954 and 1984 to see if radiation treatment would increase the rate of mortality from heart disease. Tow-thirds of the patients enrolled in the study were given radiation treatment.

The researchers excluded those who died within five years of being treated. The mean follow-up was 28 years. 

Women who had been treated were not at higher risk of dying from heart disease or stroke than their counterparts who did not receive radiotherapy, the researchers found.

However, when age was considered as a risk factor, the researchers found women who received treatment were 76 percent more likely to die from heart disease and those who received the treatment for their left breasts were 80 percent more likely to die from heart disease compared with those who received treatment for their right breast cancer.

Dr. Ronald Witteles at Stanford University was quoted as saying "Radiation injury to the heart simply doesn't manifest itself as a problem until at least 10 years later" and the risk needs to be considered when deciding which treatment to use to  treat women with breast cancer.

In the wear red month, more reports on heart disease and prevention will be published here.

David Liu, Ph.D.