Fontham’s major area of research is cancer epidemiology, with a particular interest in tobacco and nutrition-related cancers and gastric carcinogenesis. She has conducted studies of lung cancer and environmental tobacco smoke, including the largest early study of lung cancer in nonsmoking women that provided some of the critical information leading to the classification of second-hand smoke as a human carcinogen. Fontham has published extensively on stomach cancer and its risk factors, with studies of the high risk populations in the Andes Mountains of Colombia. Her recent research includes the study of innovative approaches to cervical cancer screening in hard-to-reach women and studies of the long-term human-health effects of the exposures as a result of the Deepwater Horizon Oil Spill. She is a member of Board of Scientific Counselors of the National Cancer Institute (NCI) and co-chairs the Costa Rican HPV vaccine trials working group for NCI. She served as Treasurer and is currently on the Board of Directors of the American College of Epidemiology, of which she is a Fellow. She was a member of the inaugural Editorial Board of Cancer Epidemiology Biomarkers and Prevention as Assistant Editor; Chairman of the Scientific Editorial Board of the North American Association of Central Cancer Registries; and a contributing author for both the Surgeon General's Report and International Agency for Cancer Research Carcinogenesis Monograph series. She is recipient of the Alton Ochsner Award Relating Tobacco and Health, the C.L. Brown Award for Leadership Excellence in Tobacco Prevention; the Leadership and Distinguished Service Award of the American College of Epidemiology; and the Pfizer Award for Excellence in Research, Education and Patient Care. She is the first non-physician national president of the American Cancer Society.