This observation and debate has been ongoing for a long time in medical literature. Most recently, an article in the New England Journal of Medicine concluded that adjuvant radiotherapy for breast cancer increases the rate of ischemic heart disease. The authors conclude that the risk is associated with the dose of radiotherapy to the heart and begins a few years after the treatment. Dr. Kesarwala, an expert radiation oncologist from Bethesda, reviewed the data and provided a report in the April issue of the ACR Journal Advisor. She noted that “nearly 80% of patients in this study had mastectomies and over 90% had adjuvant chemotherapy with regimens very different from those currently used. This study mixed lymph node-positive patients (48%) with lymph node-negative patients, two sub-populations with different expected overall survival who would also have received different types of radiotherapy.” Other variables such as stage, presence of internal mammary nodes, type of surgery, or details of radiotherapy were not matched between the control and treated patients.
Because the study does not provide details regarding the radiotherapy specifically, it is difficult to interpret the conclusions. The doses of radiotherapy delivered in Sweden at the time of the study varied over the decades and many of those regimens do not match what is currently practiced in this country. A final point: most of the patients who suffered from cardiac complications seem to have been treated prior to 1980.
At the Swedish Cancer Institute, we take the risk of cardiac complications seriously and we have been pioneers in developing more sophisticated approaches to delivering radiotherapy following a lumpectomy. We have introduced techniques like partial breast radiotherapy, tomotherapy, IMRT, and Airway Breathing Control as various techniques to treat patients and reduce or eliminate the dose of radiation to the heart tissue. Our approach has been simple: try to use the state of the art technology in a way that optimizes the treatment to eradicate the cancer, and spare as much of the normal tissue as is safely possible.