Breast cancer is the most common cancer among women in Sweden and more than one in ten develop breast cancer during their lifetime [1]. Screening for breast cancer by digital mammography (DM) has in early trials been estimated to result in a 20 % relative reduction in breast cancer mortality [2]. Advances in therapy have contributed further to breast cancer mortality reduction. One risk in screening is overdiagnosis, i.e. diagnosis of breast cancer which would never have led to clinical symptoms…