A study published in the British Medical Journal Tuesday raised new doubts that screening for breast cancer is the right way to save lives. Almost three-quarters of American women over 40 say they have had a mammogram, and the importance of early detection has become a familiar refrain. But the study found "that the death rates from breast cancer and from all causes were the same in women who got mammograms and those who did not," The New York Times wrote Tuesday. "And the screening had harms: One in five cancers found with mammography and treated was not a threat to the woman’s health and did not need treatment such as chemotherapy, surgery or radiation." The dangers of overtreatment raise the stakes for health professionals trying to decide what role mammography should play—and so do the realities of cost. Here are a few facts and figures about the mammogram industry's bottom line.