MONDAY, Oct. 17 (HealthDay News) -- Women who undergo mammograms every two years instead of every year have fewer false-positive results, but the trade-off is a slightly higher risk of being diagnosed with late-stage breast cancer, new research finds.
"After 10 years, biennial mammograms reduced the risk of false-positives by about one-third and, over a lifetime, that would accumulate," said Rebecca Hubbard, lead author of a study published in the Oct. 18 issue of Annals of Internal Medicine and funded by the U.S. National Cancer Institute.
But the increase in breast cancer diagnoses wasn't statistically significant, she said. And breast cancer stage was only analyzed in women who actually developed cancer.
On the other hand, among roughly 170,000 women screened between 1994 and 2006 and followed for a decade, more than half who received annual mammograms were called back at least once because of a false-positive result, and 7 to 9 percent were recommended to get a biopsy.
Fewer women -- about 42 percent -- who had biennial screening were called back because of a false-positive, while 4.8 percent were referred for a biopsy.
Having a previous mammogram for comparison purposes sliced the rate of false-positives in half.
For the study, researchers used data from NCI's Breast Cancer Surveillance Consortium.
Women undergoing once-yearly mammograms need to be prepared for possible call backs, and being prepared may reduce the anxiety around such an event, the authors stated.
This is the latest volley in an ongoing debate about when to start mammography screening in women.
In 2009, the U.S. Preventative Services Task Force (USPSTF), a government-sponsored organization, startled the world by recommending that women start mammograms at age 50 instead of 40 and then only once every two years rather than once a year.
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