A retrospective analysis of more than 110,000 women between the ages of 45 and 80 found that those who took GLP-1 medications were about 30 percent less likely to develop breast cancer than those who did not take GLP-1 medications, according to research presented today at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 10506) by Elizabeth McDonald, MD, PhD, a professor of Radiology in the University of Pennsylvania Perelman School of Medicine and a practicing breast radiologist at Penn’s Abramson Cancer Center.