THURSDAY, April 5 (HealthDay News) -- Women who have a false-positive result on their mammogram may be at higher long-term risk of developing breast cancer than those whose initial test is negative, according to a new Danish study.
However, the link between false-positive results and an increased risk of breast cancer was weaker among women who had been screened from the early 2000s on, the researchers found.
Experts have long known that screening mammograms, done in healthy women to detect breast cancer early, are bound to lead to some false-positive test results. These are results that seem to detect cancer but turn out to be false upon further testing.
However, few studies have followed these women with false-positive results long-term to evaluate what happens, said My von Euler-Chelpin, an associate professor of epidemiology at the University of Copenhagen, who led the study. The new findings were published online April 5 in the Journal of the National Cancer Institute.
"Some earlier research has found similar results, but to my knowledge there has been no study with such a long follow-up as this one," Euler-Chelpin said.
For the study, the investigators evaluated 58,000 Danish women, aged 50 to 69. They looked at those with negative mammogram results and those that turned out to be -- with further testing such as ultrasound and biopsies -- false positives. They looked at both invasive breast cancer and the early cancer known as ductal carcinoma in situ.
The average follow-up time was nearly 11 years. Women who had received false-positive results in the mid-1990s had about a 1.5 to 1.6 times higher risk of eventually developing breast cancer compared to those who had negative initial mammograms. This increased risk persisted even at six or more years, the researchers found.
For the false-positive group that underwent their mammograms
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