Mammographic breast density (MBD) may not be a household term, but it is considered an important risk factor for breast cancer. Essentially, MBD shows up in mammograms when breasts contain more glandular (milk-producing) and connective tissue than fat tissue. Women with widespread MBD have a four- to six-fold increase in risk compared with women with no density.
“People have been reluctant to provide women with this information because they didn’t want to cause unnecessary anxiety, and they didn’t have the extra resources in mammography screening programs to provide individual counseling,” says Joan Bottorff, Dean of Health and Social Development at UBC Okanagan.
“Now, however, with more and more evidence that breast density is an important risk factor for breast cancer, women should know about it so they can make decisions about things like diet that may reduce their density.”
Bottorff and colleagues with UBC’s NEXUS research team recently completed a study of 618 women 50 years of age or older with MBD greater than 50 per cent of breast volume. The findings, published this month in the Canadian Journal of Nursing Research, suggest that informing women of their MBD status — along with a pamphlet explaining breast density — is a non-threatening way to provide important personalized information about breast cancer risk at the time women receive mammographic screening test results.
Researchers followed up with women four weeks and again six months after receiving their screening test results, to see how the women had responded to the information.
“Compared to the controls, more women in the intervention group described the term ‘breast density’ correctly and recognized it as a risk factor for breast cancer,” says Bottorff. “Although at the four-week follow-up, the intervention group indicated that they were very likely to have an annual clinical breast examination more frequently than controls, no differences were detected at six months.”
Providing MBD information to women along with their mammography screening results raised awareness of MBD risk factors, it isn’t expensive, and was not found to be associated with negative psychological outcomes. However, more research needs to be done to determine whether information about MBD has different consequences for those receiving their first screening mammogram or for those with suspicious or abnormal screening results.
Co-investigators included Pamela Ratner, a Michael Smith Foundation for Health Research Senior Scholar and Coordinator of PhD Programs at UBC Vancouver’s School of Nursing, Joy Johnson, Associate Director of Graduate Programs and Research at UBC Vancouver’s School of Nursing, T. Gregory Hislop, Jane Buxton, Cornelia Zeisser, Weihong Chen, and Birgit Reime.
The research was funded by a grant from the Susan G. Komen Breast Cancer Foundation and Canadian Institutes of Health Research Investigator Awards to Bottorff and Johnson. Support was also provided by the Screening Mammography Program of British Columbia.
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