tion, and ultrasound, the trial is limited to women with dense breasts who are at high risk for breast cancer.
Because the ACRIN trial will not measure death rates, but will rely on surrogate endpoints such as lesion size, nodal status, and diagnostic yield, it cannot directly determine whether the combination of ultrasound and mammographic screening has any effect on mortality from breast cancer (reviewed in Kopans 2004).66 Rather, it is intended as a preliminary, best-case scenario of ultrasound screening for breast cancer which, given promising results, would justify broader study.6 Moreover, even if the efficacy of screening ultrasound were established, several technical and practical limitations could hinder its adoption. Chief among these is the variability of results obtained in current clinical practice.6,68,80 Ultrasound tends to be more difficult in larger and fatty breasted women. However, a systematic study of factors that influence the performance of breast ultrasound—which may include breast size and shape, as well as lesion location—has yet to be conducted.6 Finally, as it is currently performed, ultrasound demands too much physician time to be a cost-effective screening method.6
Demand for breast imaging is rising as the U.S. population ages and as increasing numbers of women require routine screening.56,119 Improved screening methods and new technologies may help keep pace with these trends, but greater capacity in both personnel and imaging facilities will also be needed to ensure patient access. These resources are also crucial to the improvement of breast cancer detection, because a robust process of assessment, adoption, and dissemination of innovative technology and techniques by practitioners requires an equally robust workforce.
Despite these mounting demands, many in the breast imaging field point to stagnant growth, if not decline, in the availability of the services they provide. Over the long term, such a trend could threaten the advancement of breast cancer detection, which is already limited by the scarcity of radiologists conducting research in this area. The development of new technology also has the potential to solve some of the problems of demand by focusing mammographic services on populations who are most at risk, although these applications are probably at least 5 to 10 years in the future. The need for and difficulty in developing a large and well-trained workforce will likely help to push for research and adoption of technology that improves our ability to target mammographic screening to those who will benefit most. This section describes key factors influencing supply and demand for breast imaging and recommended measures to ensure the accessibility and advancement of breast cancer screening.