A study found that women diagnosed with early-stage breast cancer decades ago who got radiation therapy were 56% more likely to die from heart problems later in life compared to women who didn't get radiation therapy.
Researchers looked at the medical records of 4,456 French women who were treated for early-stage breast cancer between 1954 and 1984. The average age of the women was 55. About 66% of the women got radiation therapy after surgery; 33% didn't. At the time these women were treated, radiation therapy was more aggressively used after surgery to reduce the risk of recurrence (the cancer coming back) compared to the way it's used now. This was because using chemotherapy after surgery to reduce recurrence risk wasn't common at that time.
Half the women were followed for more than 28 years, the other half for less time. More than half of the women (2,637) had died by the time this study was published; 421 of the women died from heart problems. The researchers compared the two groups of women (those who got radiation and those who didn't) to see if one group was more likely to die from heart problems.
Women who got radiation therapy were 76% more likely to die from a heart problem and 33% more likely to die from a stroke. Heart problems that caused death included plaque building up in the coronary arteries, congestive heart failure, and heart rhythm abnormalities. Heart valve damage was another heart problem that caused death and was linked to radiation therapy. While not very many women died of heart valve damage, this cause of death was 9 times more common in women who got radiation therapy compared to women who didn't.
Women who got radiation therapy for cancer in the left breast were:
- 77% more likely to die from a heart problem compared to women who didn't get radiation
- 31% more likely to die from a heart problem compared to women who got radiation therapy for cancer in the right breast
Women who got radiation therapy to lymph nodes underneath the chest wall (internal mammary nodes) were 30% more likely to die from a heart problem compared to women who got radiation to only the breast and chest wall.
Experts agree that radiation therapy improves the overall prognosis for many women diagnosed with early-stage breast cancer. Still, studies like this have found a link between radiation therapy as it was given years ago and a higher risk of heart problems. The heart is just below the chest wall. Unintentionally radiating the heart muscle, heart valves, and coronary arteries may damage the heart. Because the heart is on the left side of the chest, the heart may unintentionally be exposed to more radiation in women diagnosed with cancer in the left breast compared to women diagnosed with cancer in the right breast.
It's important to know that this study looked at women who got radiation therapy between 1954 and 1984. Since that time, advances in radiation therapy technology make it increasingly less likely that the heart and surrounding breast tissue will be unintentionally exposed to radiation. Doctors today use computers to plan radiation therapy that is extremely precise in its dosing and delivery. The computer aims just the right amount of radiation only at tissue that needs to be treated. Other new technology gives radiation oncologists wider and safer radiation energy source choices. Some radiation therapy equipment actually tracks heart beats and the movement of the lungs and effectively blocks those tissues from any radiation exposure.
If you've received radiation therapy in the past, it's important that your doctor knows about your medical history and any treatment-related risks you may have. If you've recently been diagnosed with breast cancer and radiation therapy is part of your treatment plan, you may want to ask your doctor about any potential risks for your heart. Understanding all the heart risks associated with radiation therapy is more important for women diagnosed with cancer in the left breast who may be deciding between lumpectomy with radiation therapy and mastectomy without radiation therapy.
If you're going to get radiation therapy for breast cancer, it's a good idea to ask your radiation oncologist if the technology being used is up to date. 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 breast cancer. Together, you can plan your treatment to minimize any risks.