Public Release: 

False-positive mammograms may indicate increased risk of breast cancer later

American Association for Cancer Research

Main Finding(s): Women with a history of a false-positive mammogram result may be at increased risk of developing breast cancer for up to 10 years after the false-positive result.

Journal in Which the Study was Published: Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research

Author: Louise M. Henderson, PhD, assistant professor of radiology at the University of North Carolina School of Medicine; a member of the UNC Lineberger Comprehensive Cancer Center, and an adjunct assistant professor in the UNC Gillings School of Global Public Health in Chapel Hill.

Background: In the United States, about 67 percent of women ages 40 and older undergo screening mammography every one to two years, Henderson said. Over the course of 10 screening mammograms, the chance of at least one false-positive result is 61 percent for women screened annually and 42 percent for women screened every two years. Upon receiving a positive mammogram result, women are typically referred for additional imaging. Some of those women will be further referred for a breast biopsy.

How the Study Was Conducted: Henderson and colleagues analyzed data from the Breast Cancer Surveillance Consortium (BCSC) from 1994 to 2009. The study population, which came from seven registries in different parts of the United States, included 2.2 million screening mammograms performed in 1.3 million women, ages 40 to 74 years. After the initial screening, women were tracked over 10 years, allowing researchers to evaluate the women's breast cancer risk over time.

Results: After adjusting for common factors that influence breast cancer risk, Henderson and colleagues found that women whose mammograms were classified as false-positive and were referred for additional imaging had a 39 percent higher risk of developing subsequent breast cancer during the 10-year follow-up period, compared with women with a true-negative result. Women who had a false-positive result and were referred for a breast biopsy had a 76 percent increased chance of developing subsequent breast cancer compared with women with a true-negative result.

Author Comment: In an interview, Henderson said, "Our finding that breast cancer risk remains elevated up to 10 years after the false-positive result suggests that the radiologist observed suspicious findings on mammograms that are a marker of future cancer risk. Given that the initial result is a false-positive, it is possible that the abnormal pattern, while noncancerous, is a radiographic marker associated with subsequent cancer."

Henderson cautioned that she does not want the study findings to increase anxiety over mammograms and breast health, explaining that the increase in absolute risk with a false-positive mammogram is modest.

"We don't want women to read this and feel worried," she said. "We intend for our findings to be a useful tool in the context of other risk factors" such as age, race, and family history of breast cancer.

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To interview Louise Henderson, contact Julia Gunther at julia.gunther@aacr.org or 215-446-6896.

Funding & Disclosures: This study was funded by the BCSC and grants from the National Institutes of Health. Henderson declares no conflicts of interest.

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About the American Association for Cancer Research

Founded in 1907, the American Association for Cancer Research (AACR) is the world's oldest and largest professional organization dedicated to advancing cancer research and its mission to prevent and cure cancer. AACR membership includes more than 35,000 laboratory, translational, and clinical researchers; population scientists; other health care professionals; and cancer advocates residing in 101 countries. The AACR marshals the full spectrum of expertise of the cancer community to accelerate progress in the prevention, biology, diagnosis, and treatment of cancer by annually convening more than 30 conferences and educational workshops, the largest of which is the AACR Annual Meeting with almost 19,300 attendees. In addition, the AACR publishes eight prestigious, peer-reviewed scientific journals and a magazine for cancer survivors, patients, and their caregivers. The AACR funds meritorious research directly as well as in cooperation with numerous cancer organizations. As the Scientific Partner of Stand Up To Cancer, the AACR provides expert peer review, grants administration, and scientific oversight of team science and individual investigator grants in cancer research that have the potential for near-term patient benefit. The AACR actively communicates with legislators and other policymakers about the value of cancer research and related biomedical science in saving lives from cancer. For more information about the AACR, visit http://www.AACR.org.

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