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Spotlight on Applied Research

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BCSC Drives New Knowledge About Breast Density

The "Risk-Based Breast Cancer Screening in Community Settings" (BCSC-P01) program project is leading major research efforts pertaining to breast density, including: the use of breast density for cancer risk prediction; screening effectiveness; evaluation of new technologies; what supplemental or alternative imaging should be used for women with dense breasts; and the value of and best practices for estimating and providing breast density information to women.

Breast density to predict risk

The Breast Cancer Surveillance Consortium (BCSC) was the first to report that benign breast diseases and mammographic breast density are independent risk factors for breast cancer. Findings indicated that high breast density with atypical ductal hyperplasia results in high breast cancer risk, but low breast density with benign breast disease does not significantly increase breast cancer risk (Tice et al., 2013). Additional manuscripts reporting seminal findings about breast density and risk are in progress.

Another effort, "Automated Density Measures for Estimating Breast Cancer Risk and Therapy Response," is harnessing the BCSC research infrastructure in the San Francisco Mammography Registry, in collaboration with the Mayo clinic, to compare commercial and experimental automated measures of volumetric breast density. This grant will ascertain the measure that is most strongly associated with breast cancer risk.

The BCSC is creating the first single breast cancer risk model to incorporate single nucleotide polymorphisms (SNPs), sex hormone levels, and quantitative breast density measured on the same women. They are also updating the BCSC breast cancer risk calculatorExternal Web Site Policy to improve model discrimination. The updated model will incorporate two American College of Radiology Breast Imaging-Reporting and Data System (BI-RADS) density measures and benign breast disease diagnoses.

Screening effectiveness

BCSC investigators were the first to report a benefit from annual versus biennial screening mammography for women 40-49 years of age who are at elevated breast cancer risk because of extremely dense breasts (Kerlikowske et al., 2013).

New technologies and supplemental imaging for dense breasts

BCSC investigators found that the overall rate of breast MRI (screening, diagnostic evaluation, surveillance) in community practice nearly tripled between 2005 and 2009, increasing from 4.2 to 11.5 exams per 1,000 women. Diagnostic evaluation was the most frequent clinical indication for breast MRI, followed by screening. Compared with the use of screening mammography alone, screening breast MRI was most likely to have been performed in women who were younger (less than 50 years of age), white non-Hispanic, nulliparous (has never given birth), or had any of the following: extremely dense breasts, first-degree relative with breast cancer, personal history of breast cancer, or prior breast biopsy (Wernli et al., 2013).

A grant funded by the American Cancer Society ("Performance of Screening Ultrasound as an Adjunct to Screening Mammography in Women with Dense Breast Tissue") and using data collected by the BCSC will rapidly and retrospectively compare mammography plus screening ultrasound, versus screening mammography alone, by level of breast cancer risk and level of breast density.

The BCSC is evaluating whether digital mammography plus computer-aided detection (CAD) improves mammography performance compared to digital mammography alone, according to age and BI-RADS breast density. The consortium is also evaluating performance in community practice of advanced imaging screening technologies such as breast MRI, screening ultrasound, and digital breast tomosynthesis (three-dimensional mammography) by breast density and breast cancer risk.

Manuscripts reporting on the cost effectiveness of new technologies and supplemental imaging for dense breasts are in progress.

Impact of estimating and providing breast density information to women

Several activities in this very important arena are in progress and will be covered in future issues of this newsletter.

Last Modified: 27 Jun 2014