" www.nih.gov.National Institutes of Health (NIH) is amedical research agency,omponent of the U.S. Department of Health and Human Services.National Cancer Institute (NCI) is aCancer Program and leads NIH’s efforts to dramatically reduce the prevalence of cancer and improve the lives of cancer patients and their families, through research into prevention and cancer biology, the development of new interventions, www.cancer.gov. ECOG-ACRIN Cancer Research Group (ECOG-ACRIN) is a scientific organization that designs and conducts cancer research involving adults who have or are at risk of developing cancer. www.ecog-acrin.org(link is external).The Tomosynthesis Mammographic Imaging Screening Trial (TMIST), the first randomized trial to compare two types of digital mammography for breast cancer screening isopen for enrollment. Researchers are enrolling healthy women ages 45 to 74 who are already planning to get routine mammogramsto most effectively screen women for breast cancer and help women make informed decisions about the screening tests in the future. Researchers are comparing two types of digital mammography tomosynthesis (known as three-dimensional, or 3-D) and conventional (two-dimensional, or 2-D). Although 3-D mammography, being the newer technology, is likely to detect more findings that require follow-up, it is also likely to lead to more procedures and treatments. It is not known if this newer mammography technology is reducing a woman’s risk of developing a life-threatening (advanced) cancer compared with 2-D mammography. The trial aims to find out.Researchers are collecting data on the results of every mammogram, whether the imaging shows no signs of cancer, findings suspicious of cancer, or a breast cancer. Any medical follow-ups, such as more imaging or biopsies, are also being reported. Researchers intend to follow all participants for breast cancer status, treatment, and outcomes. The vast majority of women in the study will not develop breast cancer. If a woman does receive a diagnosis of any kind of breast cancer while in the trial, she will receive treatment.In addition to data from mammograms, the trial is building a biorepository for future research on genetic markers for breast cancer by asking all participants to voluntarily submit blood samples and swabs of cells from inside the mouth (buccal cells) which could help women and their doctors decide the best ways to screen for breast cancer by evaluating their individual risk factors for developing the disease."