A study conducted at University of North Carolina at Chapel Hill found that false positive mammograms are linked to a slightly increased risk of breast cancer.

To assess cancer risk after false positives, researchers reviewed data on over 2.2 million mammograms performed in almost 1.3 million women aged 40 to 75 between 1994 and 2009.

They discovered that women who have abnormal mammogram results may be at increased risk for developing breast cancer even when follow-up tests fail to detect tumors.

“Given what we found, I would say that having a false positive (result) definitely does increase your risk for developing breast cancer,” said Louise M. Henderson, an assistant professor of radiology at the University of North Carolina School of Medicine in Chapel Hill. Henderson is lead author of the study, which was published on Wednesday in the journal, Cancer Epidemiology, Biomarkers & Prevention.

“This study confirms findings from several international studies conducted over the past decade or so that show this association between having had a false positive mammogram with a higher risk of developing breast cancer in the following five to 10 years. I think we can now state with confidence that (it) is in fact a risk factor for developing breast cancer,” said Dr. Richard Wender, chief cancer control officer for the American Cancer Society. Wender was not involved in the research.

 

False positives are so common because clinicians must strike a balance between screenings that are sensitive enough to find even the smallest abnormalities and specific enough to capture results that most likely to actually be cancer, said Dr. Richard Bleicher, a breast surgeon at Fox Chase Cancer Center in Philadelphia.

“These two characteristics are usually a trade-off,” Bleicher, who wasn’t involved in the study, said by email.

“False positives are not necessarily a completely bad thing,” Bleicher added. “They admittedly do cause anxiety. But if it ends up being that the false positives become a predictive factor for who may be at elevated risk to develop cancer, then those false positives may be an indicator of a woman’s just like any other factor that we use to predict risk, like family history or genetic testing.”