The use of mammograms has dipped since a medical task force made controversial recommendations that women in their 40s may not need to get breast cancer screenings every year, according to one of three small studies presented Monday. The studies related to this topic will be presented at the American Roentgen Ray Society annual meeting. They do not appear in peer-reviewed journals. The studies suggest that fewer physicians are recommending annual mammograms for women in their 40s, fewer patients in that age group are getting screened and that tumors found through routine mammography are more likely to be detected in early stages of cancer. The studies examined the impact of the controversial guidelines issued by the U.S. Preventive Services Task Force, a federal advisory board.