Although radiation exposure from breast cancer treatment is associated with a small risk of subsequent heart disease, the risk is lower than it was 20 years ago, according to the results of a study published early online in JAMA Internal Medicine.
Approximately 200,000 women are diagnosed with breast cancer every year in the United States alone. Treatment often involves radiation, used after surgery to kill any remaining cancer cells. This decreases the risk of local recurrence and improves survival. Like any treatment modality, however, radiation carries risks—including the increased risk of heart disease when radiation is used on the left breast, which is closer to the heart.
Because long-term breast cancer survival rates have improved dramatically in recent decades, researchers continue to look for ways to minimize long-term treatment-related complications. Researchers conducted an analysis to evaluate the risk of developing heart disease as a result of radiation treatment to the left breast—and found that the risk varies depending on the underlying risk of heart disease.
They report that the average risk of developing heart disease as a result of radiation exposure for breast cancer treatment is less than one percent. The risk increases fro woman who already have a high underlying risk of developing heart disease—in these cases, the risk may be as high as 1 in 30. In contrast, women who already have a very low underlying risk of heart disease may face odds as low as 1 in 3000, which is a tiny risk.
The researchers note that the risk of developing radiation-induced heart disease is small enough that women should not skip radiation treatment as a result of this risk.
Women who have a high underlying risk of heart disease can reduce their risk of radiation-induced heart disease in the same way that anyone might reduce their risk—through healthy diet, exercise, and avoidance of tobacco. Researchers continue to investigate changes to radiation treatment that might reduce the risk of heart disease for high-risk patients in the future.
Brenner DJ, Shuryak I, Jozsef G, et al. Risk and risk reduction of major coronary events associated with contemporary breast radiotherapy. JAMA Internal Medicine. Published early online October 28, 2013. doi:10.1001/jamainternmed.2013.11790