The Task Force now recommends against breast screening in women aged 40 to 49 years, but the harms may outweigh the benefits in all age groups. An effect of 15% and an overdiagnosis rate of 30% mean that for every 2000 women invited for screening throughout 10 years, 1 woman will have her life prolonged and 10 healthy women, who would not have breast cancer diagnosed if there had not been screening, will be treated unnecessarily (3). Furthermore, about 1000 women in the United States will have had a false-positive diagnosis (3). The psychological strain until one knows whether it was cancer can be severe. The harms caused by overdiagnosis are lifelong.