Study: Some Overtreated after Mammogram

About 15% to 25% of breast cancers found after a mammogram do not need to be treated, a new study estimates. But no one knows for sure which tumors are the bad ones. So some women get treatment they don’t need, the study authors say. The study looked at results of a mammogram screening program in Norway. Women ages 50 to 69 were offered testing every 2 years. Some areas of the country began regular screening earlier than others. Researchers compared cancer rates in areas that started early with those that started later. They estimated that the program prevented 1 death from breast cancer for every 2,500 women offered screening. But they also estimated that 6 to 10 women of every 2,500 got treatment they didn’t need. The journal Annals of Internal Medicine published the study. The Associated Press wrote about it April 3.