Screening ultrasound as an adjunct to mammography in women with mammographically dense breasts

Abstract

There are potential benefits and harms of screening ultrasound (US) to supplement mammographic screening of women with dense breast tissue. We conducted a comprehensive literature review of studies assessing the efficacy of screening US to supplement mammography among women with dense breasts. From a total of 189 peer-reviewed publications on the performance of screening US, 12 studies were relevant to our analysis. The reporting of breast cancer risk factors varied across studies; however, the study populations tended to be at greater than average risk for developing breast cancer. Overall, US detected an additional 0.3-7.7 cancers per 1000 examinations (median, 4.2) and was associated with an additional 11.7-106.6 biopsies per 1000 examinations (median, 52.2). Significant improvements in cancer detection in dense breasts have been achieved with the transition from film to digital mammography. Thus adjunctive screening with ultrasound should be considered in the context of current screening mammography performance. Clinicians should discuss breast density as 1 of several important breast cancer risk factors, consider the potential harms of adjunctive screening, and arrive at a shared decision consistent with each woman's preferences and values.

Keywords: adjunctive screening; breast density legislation; dense breasts; screening breast ultrasound.

Figure 1. Categorization of Mammographic Breast Density

Mammographic breast density categorized according to the ACR BI-RADS (almost entirely fat, scattered areas of fibroglandular density, heterogeneously dense and extremely dense) and breast density legislation criteria (nondense and dense).

Figure 2. Variability of Biopsy Rates Across Adjunct Screening Ultrasound Studies

The number of biopsies (per 1,000 examinations) is reported across adjunct screening ultrasound studies with 95% confidence intervals.^–, The biopsy rates from the Giuliano, et al and Girardi, et al studies were not included in their studies.^, These biopsy rates are in addition to the biopsy rates for mammographic examinations with positive results (10.2 biopsies/1,000 examinations).