A report in the Journal of the National Cancer Institute finds mammograms detect few cancers in women under the age of 40 but cause expense and anxiety because women frequently get "false positives" that require follow-up to rule out cancer. Radiologist Bonnie Yankaskas of the University of North Carolina at Chapel Hill examined the records of women aged 18 to 39 when they got their first mammograms starting in 1995, following them for a year to see what happened. There were no tumors found among the women under 25. For women aged 35 to 39, about 12 per 1,000 got called back for further checks after the mammogram produced a suspicious-looking lesion. Very few actually had a tumor. "In a theoretical population of 10,000 women aged 35 to 39 years, 1,266 women who are screened will receive further workup, with 16 cancers detected and 1,250 women receiving a false-positive result," according to Dr. Bonnie Yankaskas. "Harms need to be considered, including radiation exposure because such exposure is more harmful in young women, the anxiety associated with false-positive findings on the initial examination, and costs associated with additional imaging." See http://www.raysahelian.com/mammography.html