Radiation Treatment for Breast Cancer Increases Heart Disease Risk

Written by Rebekah Kuschmider
Medically Reviewed by Jabeen Begum, MD on October 29, 2021
2 min read

Many breast cancer patients get radiation to treat their cancer. It's a highly effective form of treatment with clear benefits. But like all cancer treatments, it comes with a risk of long-term effects.

In 2021, researchers released a study that looked at coronary artery disease (CAD) in breast cancer survivors who had gotten radiation treatment. The study looked at 972 women who had been diagnosed between 1985 and 2008. They discovered that having radiation therapy could increase the risk of CAD.

The incidence of heart disease in the study varied according to age at diagnosis and which side was treated with radiation.

  • Age 25 to 29 at time of diagnosis with radiation on right breast: 0% incidence of CAD
  • Age 25 to 29 at time of diagnosis with radiation on left breast: 5.9% incidence of CAD
  • Age 40 to 54 at time of diagnosis with radiation on right breast: 6.8% incidence of CAD
  • Age 40 to 54 at time of diagnosis with radiation on left breast: 18.7% incidence of CAD

In the general population of women in the U.S., the incidence of CAD is 0.9% among women 20 to 39 years old. Among women aged 40 to 59 years, the incidence is 6.6%. That's similar to the rates for study participants who had radiation on their right breasts. 

The researchers concluded that radiation on the left side of the body increases your risk of heart disease later in life. The research team noted that this doesn't mean radiation isn't a good treatment option.

"It is important that clinicians caring for younger breast cancer patients communicate the importance of radiation therapy for breast cancer while explaining the need for long-term attention to the risk of heart disease, particularly for women receiving left-sided radiation therapy," said study author Gordon Watt, Ph.D.

If you've been diagnosed with breast cancer and need radiation therapy, talk to your doctor about the possibility of developing heart disease later. They can help you decide how to manage that risk over the long term.