False-positive mammography today means elevated cancer risk later

Women who heave a sigh of relief upon learning their breast-cancer diagnosis at screening is a false positive shouldn’t let their guard down. A study in the December edition of Cancer Epidemiology, Biomarkers & Prevention shows that these patients are at increased risk of developing the disease for at least a decade.

Drawing from close to 49,000 diagnosed cancers and more than 12 million person-years of data gleaned between 1994 and 2009 in the National Cancer Institute’s Breast Cancer Surveillance Consortium, Louise Henderson, PhD, of the University of North Carolina and colleagues found that women who had a false positive with additional imaging recommendations had a higher risk of developing breast cancer (adjusted hazard ratio, 1.39) than those with a true-negative exam.

So did women with who had a false positive with a recommendation for biopsy (adjusted hazard ratio, 1.76).

The team found a higher proportion of false positives among women with heterogeneously or extremely dense breasts, although breast density did not affect the relationship between false-positive mammograms and subsequent cancer for most women.

Eye-opening as the most newsworthy takeaway may be—across the board, women with a false-positive result had persistently increased risk of developing breast cancer 10 years after the false-positive examination—the finding is consistent with several European studies, the authors note.

In remarks released by the American Association for Cancer Research, publisher of the CEB&P journal, Henderson says abnormal but noncancerous patterns that produce false positives could be radiographic markers associated with subsequent cancers.

“Our next steps are to consider how to incorporate a prior false-positive mammogram and biopsy results into risk-prediction models for breast cancer,” she adds before pointing out that that age, race, family history and other factors figure just as prominently, if not more so, in determining a woman’s risk in the BCSC risk calculator.

“We don’t want women to read this and feel worried,” Henderson says. “We intend for our findings to be a useful tool in the context of other risk factors and assessing overall breast cancer risk.”