(NaturalNews) Mammograms deliver overwhelmingly more false positive results than true positives in women under the age of 40, according to a new study conducted by researchers from the University of North Carolina-Chapel Hill and published in the Journal of the National Cancer Institute.
In a false positive result, a mammogram detects signs of a tumor that turns out to be non-cancerous or otherwise not dangerous to a woman's health.
"In a theoretical population of 10,000 women aged 35 to 39 years, 1,266 women who are screened will receive further workup, with 16 cancers detected and 1,250 women receiving a false-positive result," the researchers wrote.
"Harms need to be considered, including radiation exposure, because such exposure is more harmful in young women; the anxiety associated with false-positive findings on the initial examination; and costs associated with additional imaging."
The researchers examined the medical records of more than 117,000 U.S. women who got their first mammograms between the ages of 18 and 39. In the ensuing year, not a single woman under the age of 25 was diagnosed with breast cancer. For women between 35 and 39, 12.7 percent were called back for further tests but only 0.16 percent actually had cancer.
Because breast cancer rates in young women are so low, screening them is like "looking for a needle in a haystack," lead researcher Bonnie Yankaskas said.
Nonetheless, 29 percent of U.S. women between the ages of 30 and 40 say they have had at least one mammogram.
Reacting to the study, the American Cancer Society reiterated that it does not recommend screening in women under the age of 40.
"We have been concerned that some have been encouraging that screening begin at younger and younger ages, when the science does not support it as beneficial," chief medical officer Otis Brawley said.
Due to the risks associated with radiation and false positives, the U.S. Preventive Services Task Force now only recommends screening for women aged 50 and older.