Breast cancer screening is debated passionately among those who advocate for very aggressive screening and other experts who believe that screening can be harmful. The arguments for all sides of the debate are best understood by knowing the numbers of women who will benefit or be harmed by breast cancer screening. Both sides of the debate are explained in this podcast by Nancy Keating, MD, and Lydia Pace, MD, both from the Brigham and Women's Hospital and Harvard Medical School in Boston.