evidence: That was the reason behind a worldwide push to have every woman get regular mammogram screenings. The idea was to lower the rates of advanced cancers and ultimately deaths from the disease. But in a new study published in BMJ, researchers show that mammography did little to reduce either deaths or advanced breast cancer over a period of 23 years in the Netherlands. Instead, they found that the X-ray based test designed to pick up tumors led to overdiagnoses 60% of the time. [...] Mammography doesn’t actually pick up tumors but rather the changed breast tissue surrounding tumors; it’s possible that many advanced cancers are growing without significantly changing breast tissue, and therefore not getting picked up by mammograms in time. [...] Autier says that he was a champion of mammogram screening in previous decades, believing that the benefits for women in detecting cancer outweighed the harms of developing advanced cancer. However, he says the evidence no longer supports that position. "We, and I include myself in the we, promoted mammography screening for plenty of good reasons then," he says. "I am not glad at all that we found [in this study] that mammography is probably not the ideal solution for protecting women from breast cancer. There is no good evidence that mammography makes a difference in mortality and if it does, it’s probably marginal. But the overdiagnosis toll is enormous."