Lise Bech Jellesmark Thorsen is a clinical oncologist at the Department of Oncology, Aarhus, Denmark. Her research has been centered mainly within the field of regional radiotherapy in early breast cancer and the delicate balance between harms and benefit from irradiation. She is the lead researcher on the Danish Breast Cancer Group Internal Mammary Node study (DBCG-IMN), and is involved in a number of other studies based within the DBCG.