New research adds clarity to supplemental breast cancer screening debate

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Evan Godt, Editorial Director

It seems we are starting to see the debate over appropriate supplemental screening for breast cancer with a little more focus and a clearer picture of who would benefit most, thanks to some interesting new research.

One of our top stories this week featured a study published in Annals of Internal Medicine that found that not all women with dense breast tissue are at very high risk for breast cancer. However, lead author Karla Kerlikowske, MD, of San Francisco Veterans Affairs Medical Center and the University of California, San Francisco, and colleagues also showed that by combining important information about breast density with other risk factors, women who are particularly at risk for an interval cancer between regular mammograms can be identified and perhaps receive counseling about additional screening.

The study featured data from 365,426 women who had undergone more than 800,000 screening mammography exams. The authors noted the patients’ BI-RADS breast density assessment, as well as five-year cancer risk as determined by the Breast Cancer Surveillance Consortium (BCSC) model. This model includes factors such as age, biopsy history, race/ethnicity and history of breast cancer in first-degree relatives.

Using these figures, Kerlikowske and colleagues found that the women who were at the highest risk for an interval cancer either had a BCSC five-year risk of 1.67 percent and extremely dense breasts, or a BCSC five-year risk of 2.5 percent and heterogeneously dense breasts. Nearly one-quarter of the women with dense breasts in the study population fell into one of these two groups.

As breast density notification laws continue to spread around the country, it’s important for patients and their providers to understand the ramifications of being classified as having dense breast tissue. I’ve always felt that patients should have the right to this information, but have been sympathetic to the arguments made by some that the legislation is ahead of the science. In an editorial accompanying the study in Annals of Internal Medicine, Nancy C. Dolan, MD, and Mita Sanghavi Goel, MD, MPH, of Northwestern University Feinberg School of Medicine in Chicago noted the importance of the findings showing that breast density alone should not guide supplemental screening decisions, but that incorporating other risk assessments, such as the BCSC five-year risk, into a mammography report along with density information can aid discussions of additional screening.

Dolan and Goel also pointed to a number of other lingering issues with regard to supplemental screening. More than 27 million women aged 40 to 74 have heterogeneous or extremely dense breasts, so we’re talking about a very large group of patients. The ideal supplemental screening strategy is still a question, with ultrasound, MR and tomosynthesis all being discussed as options. And then there is the issue of payment, as supplemental screening is not routinely covered by insurance except in a few states.

Much more must be learned, but work like that of Kerlikowske and colleagues is definitely bringing clarity to the discussion. Maybe those who said the notification laws were ahead of the science had a point, but the science is catching up.

-Evan Godt
Editor – Health Imaging