False-Positive Mammograms Could be a Marker of Future Breast Cancer Risk

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, revealed a study published in Cancer Epidemiology, Biomarkers & Prevention. Louise M. Henderson, 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, said, "In the United States, about 67% of women aged 40 and older undergo screening mammography every one to two years. Over the course of 10 screening mammograms, the chance of at least one false-positive result is 61% for women screened annually and 42% 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."

The research team analyzed data from the Breast Cancer Surveillance Consortium (BCSC) from 1994 to 2009. The study population came from seven registries in different parts of the United States, and included 2.2 million screening mammograms performed in 1.3 million women, aged 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.

After adjusting for common factors that influence breast cancer risk, the researchers found that women whose mammograms were classified as false-positive and were referred for additional imaging had a 39% 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% increased chance of developing subsequent breast cancer compared with women with a true-negative result.

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, "I do not want the study findings to increase anxiety over mammograms and breast health. The increase in absolute risk with a false-positive mammogram is modest. We don't want women to read this and feel worried. 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."

Source-Eurekalert