Declines in several key cancer-screening procedures among the elderly can be linked to shifts in screening guidelines issued by major public health organizations, according to recently released findings by Yale researchers. James Yu, associate professor of therapeutic radiology at the Yale School of Medicine, and Sean Maroongroge, a third-year medical student, gleaned data from Medicare billing records from 2000 to 2012, analyzing more than 230 million screenings for prostate, breast, and colorectal cancers. Yu, a member of the Yale COPPER Center (Cancer Outcomes, Public Policy, and Effectiveness Research Center), and Maroongroge, also tracked evidence-based screening guidelines issued by five prominent organizations: the U.S. Preventive Services Task Force (USPSTF), the American Cancer Society (ACS), the American College of Obstetricians and Gynecologists (ACOG), the American College of Gastroenterology (ACG), and the American Urological Association (AUA). They found that the rates for mammography, which is the primary means of screening for breast cancer, declined 7.4 percent overall during the period studied; prostate screening rates rose 16 percent during the first seven years studied then declined to 7 percent less than the 2000 rate by 2012. Colorectal cancer screening rates also dropped overall.