False Positive On Mammogram May Actually Signal Impending Breast Cancer

A false positive on a mammogram may, in fact, signal heightened breast cancer risk, suggests a new study.

Women who get a false positive on their yearly mammograms are at a slightly higher risk of developing breast cancer, indicates a study conducted at the University of North Carolina at Chapel Hill. To ascertain the peculiar pattern, researchers studied more than two million mammograms performed on 1.3 million women ages 40 to 74 at health clinics across the United States between 1994 and 2009, reported CNN.

The researchers discovered that women who had false-positive mammograms were at increased risk of developing breast cancer over the following decade. This pattern was predictable even when follow-up tests failed to detect tumors. If mammogram results are abnormal, it is common practice to conduct additional follow-up tests to rule out cancer. Thereafter, doctors advise a biopsy to confirm if the suspicious cell growth is malignant, which is a surefire indicator of breast cancer.

False Positive On Mammogram May Actually Signal Impending Breast Cancer
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The research indicated that after a false-positive mammogram, the aggregate absolute cancer risk over a decade isn’t much bigger as compared to women who have always had a negative test result. However, compared to women with negative results, those with false positives had 39 percent greater odds of developing cancer if additional imaging found the mammogram was a false alarm, reported Fox News. What’s even more alarming is that the women who had false-positive results and conducted biopsies had a 76 percent chance of developing breast cancer.

Speaking about the study, Dr. Richard Wender, chief cancer control officer for the American Cancer Society, said, “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.”

Peculiarly, the study also indicated that about one in 100 women who had a false positive and followed up with a single imaging test went on to develop breast cancer within the following 10 years. Moreover, two out of 100 women who had a false positive followed by a biopsy developed breast cancer. Researchers attributed the increase in risk to the fact that the radiologist had ordered a biopsy because the abnormality was serious and warranted a biopsy, said Louise M. Henderson, an assistant professor of radiology at the University of North Carolina School of Medicine in Chapel Hill.

“Given what we found, I would say that having a false positive (result) definitely does increase your risk for developing breast cancer.”

Of the mammograms studied, about 180,000 were false positive. The mammogram is considered a false positive when the initial test detects an abnormality in the breast tissue, but subsequent imaging and the biopsy test does not indicate cancerous growth. Moreover, the mammogram is considered a false positive if the woman does not develop breast cancer in the year after the mammogram was conducted. The rest of the tests studied in the research were true negatives, which means there was no abnormality detected in the first test and the women didn’t develop breast cancer in the following year.

The American Cancer Society recently updated their recommendation for mammograms. Interestingly, while the previous recommendations asked women over 40 to go for yearly tests, the new guidelines have raised the age to 45. Women over 54 can opt for a mammogram every alternate year, suggests the society.

If detected early, breast cancer is treatable. Fortunately, newer testing techniques could soon make mammograms obsolete. But this study does indicate that a false positive could, in fact, be an early sign to be extra cautious.

[Photo by Mychele Daniau/Getty Images]