July 01, 2019
2 min read

Combining 5-year risk assessment, breast density may be more predictive for advanced breast cancer

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Instead of targeting all women with dense breasts, combining a 5-year risk assessment with breast density may be a more efficient strategy to determine which women are at high risk for advanced breast cancer and could most benefit from supplemental imaging discussions, according to a study published in JAMA Internal Medicine.

“Federal legislation proposes requiring that screening mammography reports to practitioners and women incorporate breast density information and that women with dense breasts discuss supplemental imaging with their practitioner given their increased risk of interval breast cancer,” Karla Kerlikowske, MD, of the University of California, San Francisco, and colleagues wrote. “We aimed to identify women undergoing routine screening at highest risk of advanced breast cancer who may benefit most from supplemental imaging and/or highest risk of false-positive results from screening who may undergo more harm from supplemental screening.”

Researchers conducted a prospective cohort study of 638,856 women aged 40 to 74 years who had screening digital mammograms taken between January 2005, and December 2014 (mean age, 56.5 years).

Based on the Breast Imaging Reporting and Data System (BI-RADS), breast density was categorized as almost entirely fat, scattered fibroglandular densities, heterogeneously dense or extremely dense.

The 5-year invasive breast cancer risk was calculated using the Breast Cancer Surveillance Consortium (BCSC) risk calculator. Risk was categorized as low (0 to < 1.00%), average (1% to 1.66%), intermediate (1.67% to 2.49%), high (2.5% to 3.99%) and very high (>3.99%).

Researchers then combined breast density and 5-year risk categories to determine which women were at high risk for advanced cancer.

The primary outcome of the study was the development of advanced breast cancer (stage IIB or higher) within 12 months of screening mammography.

Researchers found that women with dense breasts — made up of both heterogeneously and extremely dense — accounted for 47% of the study population and 60% of advanced cancers.

Combining a 5-year risk assessment with breast density may be a more efficient strategy to determine which women are at high risk for advanced breast cancer and could most benefit from supplemental imaging discussions.
Source: Adobe Stock

Researchers determined that the strategy of combining density category with 5-year risk reduced the number of supplemental imaging discussions to 1,097 compared with 1,866 for the consideration of density alone.

“Current breast density state and federal notification laws encourage health care professionals to counsel women about how dense breasts can mask or hide breast cancers and increase risk and about the possible need for supplemental or alternative screening options,” the researchers wrote. “However, studies consistently report that women can experience anxiety or concern in response to breast density notification, and most practitioners are not prepared to counsel women about breast density and are uncertain about offering supplemental imaging. Our findings provide important information to guide women and practitioners about when supplemental imaging may be most beneficial and when it would not. The most efficient strategies identified women at high risk of advanced breast cancer based on breast density and BCSC 5-year risk.” – by Melissa J. Webb

Disclosures: Kerlikowske reports being a member of the International Working Group on Risk Assessment and Strategies for Breast Cancer Screening and Prevention, sponsored by the Breast Cancer Research Foundation and the American Cancer Society. She also reports receiving grants from Google Sciences and consultation with Grail. Please see the study for all other authors’ relevant financial disclosures.