Radiation-induced ischemic heart disease in breast cancer--a review

It is well established that adjuvant radiotherapy (RT) reduces loco-regional recurrences in breast cancer. The effect on overall survival, on the other hand, is a much-debated issue. Some old trials with a long follow-up as well as the first report on the overview of the randomized RT trials initiated before 1975 showed a reduced survival among irradiated patients compared with the surgical controls. In the update of the overview this proved to be due to cardiac deaths. In two more recent studies, adjuvant RT in the postmastectomy setting improved the survival of node-positive premenopausal patients who were also treated with chemotherapy. In one of these trials it was indicated that cardiac mortality was not increased. There are few data concerning the cardiac side effects of RT after conservative surgery. Some studies suggest that radiation-induced heart disease may be a potential problem also among these patients. Therefore, the search for both the causes of radiation-induced heart disease and preventive measures is crucial issues in breast cancer radiation oncology.