Dense breast tissue is common in younger women. Dense breast tissue absorbs significantly more radiation during mammography compared with fatty breast tissue (1). This occurrence reduces the accuracy of mammography to detect breast cancer in women with dense breast tissue (2, 3). Currently, screening mammography remains the most useful tool for breast cancer detection and consistently has demonstrated a reduction in breast cancer mortality. Nonetheless, mammography does not detect all breast cancer.
Women with dense breasts (Breast Imaging Reporting and Data System [BI-RADS] category 3 and 4) have a modestly increased risk of breast cancer and experience reduced sensitivity of mammography to detect breast cancer (see Table 1) (2). Although categories have been established, the assessment of breast density is subjective and based on the opinion of the radiologist. In women with heterogeneously dense or extremely dense breasts, digital mammography has been shown to be more effective compared with film mammography for breast cancer screening (2). Numerous states have passed legislation that require health care providers to inform women of the modest increased risk of breast cancer and reduced sensitivity of mammography, and several states require practitioners to discuss supplemental tests to screening mammography for women with dense breasts. Current published evidence does not demonstrate meaningful outcome benefits (eg, reduction in breast cancer mortality) with supplemental tests (eg, ultrasonography and magnetic resonance imaging) to screening mammography or with alternative screening modalities (eg, breast tomosynthesis or thermography) in women with dense breasts who do not have additional risk factors. Evidence is lacking to advocate for additional testing until there are clinically validated data that indicate improved screening outcomes.
The American College of Obstetricians and Gynecologists (the College) does not recommend routine use of alternative or adjunctive tests to screening mammography in women with dense breasts who are asymptomatic and have no additional risk factors. The College strongly supports additional research to identify more effective screening methods that will enhance meaningful improvements in cancer outcomes for women with dense breasts and minimize false-positive screening results. The College recommends that health care providers comply with state laws that may require disclosure to women of their breast density as recorded in a mammogram report.
1. Boyd NF. Mammographic density and risk of breast cancer. Am Soc Clin Oncol Educ Book 2013:57–62.
2. Pisano ED, Gatsonis C, Hendrick E, Yaffe M, Baum JK, Acharyya S, et al.. Diagnostic performance of digital versus film mammography for breast-cancer screening. Digital Mammographic Imaging Screening Trial (DMIST) Investigators Group [published erratum appears in N Engl J Med 2006;355:1840]. N Engl J Med 2005;353:1773–83.
3. Breast Cancer Surveillance Consortium. Evaluating screening performance in practice. Bethesda (MD): National Cancer Institute; 2004. Available at: http://breastscreening.cancer.gov/espp.pdf
. Retrieved December 18, 2013.