Posted: March 3, 2013

For years Oncologists and their patients have wondered about whether it was a good idea to radiate the left breast for cancer considering the heart was directly in the path of the beam.  Now from Scandinavia is the answer to the question, published in the March 14 issue of the New England Journal of Medicine.    If you want the actual article email Dr. Stark on the form at the right of this page.   The authors looked at the cumulative incidence of heart disease in such women and made several important observations.  First, the higher the radiation dose, the more likely you were to develop heart disease, specifically coronary artery disease, either angina or a frank heart attack, and you were more likely to die from your heart condition.  Your risk doubles over that of the general population for higher doses to the heart.   Secondly while patients whose left breast was irradiated were at particular risk, women with right breast cancer were not home free, as  their risk was higher than baseline, although not as high as women with left breast cancer.  Thirdly the risk never goes away for as long as it is studied — up to twenty years in this trial, and the risk is cumulative.   Fourthly, women with an underlying risk of heart disease — by virtue of family history, high cholesterol, high blood pressure and the like — were at special risk of developing heart disease.  Fifth, the risk increased with the age of the patient.  What the authors did not do but should have was to create a hazard function to show when the risk peaked after the radiation was over.  All of this is sobering and reminds us that in medicine there is no free lunch, and the law of unintended consequences is always out there.