Say you're a woman who had a screening mammogram, and the radiologist found something suspicious. It's recommended that you follow up maybe with ultrasound, or with a needle biopsy. So you do that too, and the results are reassuring. The lesion first found on the mammogram is not any type of cancer that is, it was a so-called "false-positive" so you're off the hook. Right?
Well, maybe not, according to a study just published in the journal Cancer Epidemiology, Biomarkers & Prevention.
Dr. Louise M. Henderson from the UNC Chapel Hill School of Medicine in North Carolina and colleagues examined the possibility that even a false-positive screening mammogram might have implications for a woman's later risk of developing cancer.
The researchers used data from the Breast Cancer Surveillance Consortium obtained between 1994 and 2009. Information from women between the ages of 40 to 74 years who had had either a false-positive (followed by additional testing) or a true-negative (no suspicious lesion was found) screening mammogram were included in the study. Over the period examined, nearly 49,000 cancers were diagnosed in the 1.3 million women with screening mammograms.
Women with a false-positive mammogram had an increased risk of developing breast cancer that was 35 or 76 percent greater than the risk of women with true-negative screening mammograms, depending on the type of follow-up the women received. The risk was higher for women who had had a recommendation for biopsy after the initial mammogram. This difference is indicative of the different types of non-cancerous lesions a woman might have a breast biopsy, rather than an ultrasound, might point to a lesion that is more likely to turn into a malignancy.
However, in their discussion, the authors pointed out that these increased risks should not cause women undue alarm, since the increases were "modest." Instead, they note that the real value of this study is its addition to the complex of risk factors women may have, such as family or personal history.