Breast Cancer Screenings

Mammography false alarms linked with later tumor risk
The American Cancer Society recommends breast cancer screenings for women who are in good health starting at age 40. But, a growing number of researchers have questioned the benefits of annual mammograms since 2009 when the United States Preventive Services Task Force first recommended that screening be done every two years and be generally restricted to women aged 50 to 74.
Now, a new study shows women with mammograms that produce false positives have a heightened risk of being diagnosed with breast cancer years later, but the reason why this is–is uncertain.
An increased risk of breast cancer among women with false positive mammograms has been reported before. The new sturdy attempts to estimate the extra risk while taking into consideration that doctors may have missed the cancer in the previous diagnosis. According to the lead author in the new study, physician mistakes regarding missing cancers are only is a small percentage of the increased risk.
A mammogram is considered false positive when it suggests possible breast cancer but additional screenings or a biopsy fails to find it. The increased risk of breast cancer occurring, does not explain most of false-positive mammograms. Radiologists reread the original mammograms and found that doctors had actually missed the cancer in 72 of the 295 women, for a false-negative rate of 1.5 percent. Even after taking those missed cancers into account, however, the researchers found that women with false-positive mammograms were still 27 percent more likely to be diagnosed with breast cancer years later, compared to women with only negative test results.
The risk was slightly higher in women who had surgical biopsies that turned out to be negative. The risk of a false-positive test over 10 mammograms ranges from 58 percent to 77 percent in the U.S.
There are those that wonder if there is an inherent biology of the breast makes it suspicious and it puts a woman at higher risk, but no one knows for sure.
Should women who get false-positive mammograms be followed more closely by their doctors, or if false-positive patients should be screened differently.
Some now believe that the excess rate of breast cancer among women who have had false-positive mammograms points to the need to personalize screening programs for women.
A risk calculator app, to guide women in deciding how often to get mammograms, is being developed at the University of California. The calculator considers a range of factors, including age, race, previous breast cancer, family history and breast density. The average five-year breast cancer risk for a 50-year-old white woman with no prior family history of breast cancer is 1.25 percent, the calculator shows. It ranges from less than 1 percent, to 2.70 percent, depending upon breast density, for the same woman with a history of a prior breast biopsy, regardless of whether the biopsy was positive or negative.
Getting a mammogram every other year instead of annually did not increase the risk of advanced breast cancer in women ages 50 to 74, according to a study that was published last year. The recommendation to reduce the frequency and delay the start of mammography screening was based on research showing the risk of false-positive results – which needlessly expose women to the anguish of a possible breast cancer diagnosis and the ordeal of further testing – outweighed the benefits of detecting cancers earlier.