Per Hall

Per Hall, MD, PhD is Professor of Oncology at the Karolinska Institutet and Director of the landmark KARMA (Karolinska Mammography Project for Risk Prediction of Breast Cancer) study, and is one of the world's leading scientists in mammographic density, dense breast screening, and breast cancer risk prediction. The KARMA study, a prospective population-based cohort that has enrolled over 70,000 women in Sweden, has generated transformative insights into how mammographic density interacts with genetics, hormonal exposures, and lifestyle factors to determine individual breast cancer risk. Professor Hall's group developed and validated the KARMA risk prediction model, which integrates mammographic density with polygenic risk scores, hormonal and reproductive factors, and family history, demonstrating substantially improved discriminative ability compared with conventional risk models. This work has formed the scientific basis for a paradigm shift toward individualized, risk-stratified screening in breast cancer—a model in which women with high mammographic density and elevated polygenic risk scores receive supplemental MRI screening, while low-risk women may be reassured with less frequent mammography. He has led pivotal studies demonstrating that abbreviated breast MRI detects a disproportionate share of interval cancers in dense breast tissue, and has collaborated on randomized trials of supplemental MRI screening in the Nordic countries. With over 250 publications and major funding from the Swedish Cancer Society, Professor Hall is a driving force behind the global movement toward precision breast cancer screening.