As anyone who has had chemotherapy or radiation knows, cancer treatments and collateral damage go hand-in-hand. For quite some time, one of the consequences we’ve been most concerned about is the effect that radiation can have on the heart. A new study in New England Journal of Medicine tells us more about that risk—and how long it lasts.
The study followed 2168 women with breast cancer who were treated with radiation between 1958 and 2001 in Sweden and Denmark. During that time, 963 of these women developed a serious heart problem and some died from heart disease. But not all women were equally at risk. The risk rose in proportion to the amount of radiation they had received and was higher in women who had cancer in their left breast (which is closer to the heart) than in women who had cancer in their right breast. It was also higher in women who were overweight, had diabetes, or smoked—other known risk factors for heart disease. Most interesting was the fact that the risk persisted long after the radiation exposure with 33 percent of the women developing heart problems 10 to 19 years after their breast cancer treatment and 23 percent not experiencing problems until 20 or more years later.
This study should not dissuade women from getting radiation for breast cancer or DCIS. Much of the radiation given to these women was 10 or 20 years ago, when the technology was more primitive. But even today women should make sure that the facility that is doing the radiation is up to date on the latest techniques. For example, the USA Today article about this study notes that M. D. Anderson Cancer Center (and probably other centers as well) are trying a new technology that times the radiation dose to a woman’s breathing, delivering the radiation as she inhales, which pushes the heart down, and stops it as she exhales.
Other researchers are investigating whether having women lay on their stomachs, rather than on their backs (so that the breast hangs down away from the heart) can reduce this risk.
In an editorial accompanying the published study, Dr. Javid Moslehi, co-director of the Cardio-Oncology Program at Brigham and Women’s Hospital in Boston, bring up another important point: more effort needs to be made to bring cardiologists into discussions about radiation, so that they can provide their expertise during treatment planning and add previous radiation therapy to their list of risk factors for heart disease.
By no means do I think that a woman should avoid getting radiation therapy for her breast cancer because of the possible future risk of heart disease. But she should be aware of the risk herself and remind her doctors in the future. In addition we all should look to radiation therapists to continue to develop ways of delivering life-saving radiation that decreases or eliminates the collateral damage it can cause.