For women diagnosed with early-stage breast cancer, lumpectomy followed by radiation therapy has been shown to be as effective as mastectomy without radiation for removing the cancer AND minimizing the risk of the cancer coming back (recurrence). Radiation therapy after lumpectomy can destroy any cancer cells that may have been left behind after surgery, making recurrence less likely. Some women who have mastectomy may also have radiation after surgery. Experts agree that radiation therapy improves the overall prognosis for many women diagnosed with early-stage breast cancer.
Still, studies have found a link between radiation therapy for breast cancer and a higher risk of heart and lung problems, especially if the cancer is in the left breast, the same side as the heart.
Now a study looking at women diagnosed with breast cancer who were treated with radiation therapy between 1958 and 2001 found these women had a higher risk of heart problems later in life.
The research was published in the May 14, 2013 issue of the New England Journal of Medicine. Read the abstract of "Risk of Ischemic Heart Disease in Women after Radiotherapy for Breast Cancer."
The study looked at 2,168 women who had been diagnosed with breast cancer and treated with radiation therapy between 1958 and 2001 in Sweden and Denmark. They compared these women’s risk for heart problems with the risk of similar women who had been diagnosed with breast cancer but hadn’t been treated with radiation.
The researchers found that for every gray (a gray is the basic unit of radiation) of radiation the heart was exposed to, the risk of heart problems when went up about 7%. The average radiation dose to the heart was 6.6 gray for women with cancer in the left breast and 2.9 gray for women with cancer in the right breast.
This increase in risk started in the first 5 years after radiation treatment, but seemed to last for about 20 years after treatment. Women who already had heart problems or risk factors for heart problems (high blood pressure, high cholesterol, diabetes, smoking) had a greater increase in the risk for heart problems.
While the results of this study are troubling, it’s important to keep several things in mind:
- This study looked at radiation therapy given between 1958 and 2001. Advances in radiation therapy since that time – and especially since 1958 – have greatly reduced the amount of radiation exposure to the heart, lungs, and other healthy tissue.
- Doctors now use computers to plan radiation therapy that is extremely precise in dose and delivery.
- A type of radiation therapy equipment used today (called respiratory gating) tracks heart beats and lung movement and effectively blocks those tissues from radiation exposure.
- Other tools, such as intensity modulated radiation therapy, allow the radiation oncologist to change the intensity of the radiation during treatment to ensure the tissue at risk receives an even dose and to avoid healthy tissue.
- Doctors may have some women lie face down (also called “prone”) to receive radiation therapy to reduce the amount of radiation that unintentionally reaches the heart and lungs.
- Some radiation treatment fields, such as the internal mammary lymph node treatment field, which is right in front of the heart, are more likely to expose the heart to radiation. It’s a good idea to ask your doctor which treatment fields will be included as part of your radiation therapy. If the internal mammary lymph node treatment field is included, you may want to ask if that treatment field is necessary.
“This study is important, but it looked at old-fashioned radiation techniques,” said Breastcancer.org Chief Medical Officer Marisa Weiss, M.D., a radiation oncologist. “Today, we carefully sculpt and customize – in three dimensions – the way radiation is delivered. We’re also aware of each patient’s unique situation, including other treatments that may affect the heart, such as Adriamycin and Herceptin, and other heart risk factors, such as smoking or high blood pressure. The good news is that modern technologies help us avoid or dramatically reduce any radiation exposure to the heart.”
If you’ve been diagnosed with breast cancer, you and your doctor will consider the characteristics of the cancer, your unique situation, your surgical options, and your treatment options after surgery when creating your treatment plan. If you choose lumpectomy, it’s very likely that radiation will be recommended after surgery. If you choose mastectomy, radiation after surgery may or may not be recommended for you. Talk to your radiation therapy treatment team about how they’ll make sure that you get only the radiation therapy required to effectively treat the cancer. Together, you can plan your treatment to minimize any risks.
You can learn more about radiation to treat breast cancer in the Breastcancer.org Radiation Therapy section.