A new UC Davis study found that women with false-positive mammograms requiring additional imaging or biopsy were less likely to return for follow-up screening.

These are concerning findings since false-positives are a common occurrence in screening mammography, and often occur in patients at increased risk of breast cancer in the future.

"False-positive results are a common and necessary part of the screening process," Diana Miglioretti, lead author and division chief of biostatistics at UC Davis, told HCB News. "Because screening mammograms are performed in women without symptoms, the vast majority of whom will not have cancer, the exam is limited to two views per breast."
In most cases, additional imaging will come back negative, but women with false-positives should return for screening every one to two years because they are at increased risk of being diagnosed with breast cancer in the future. There is no concrete explanation for this, but Miglioretti speculates that it could be because certain characteristics like higher density or calcifications lead to more false positive results and are also associated with a higher risk of developing breast cancer.

The study analyzed data from over 3.5 million screening mammograms that were performed between 2005 and 2017 on over one million patients aged 40 to 73 around the country. They found that 77% of women with a negative mammogram returned for subsequent screening, but only 61% of those with a false-positive requiring an additional mammogram in six months to confirm results actually returned for future screening.

For women who were recommended a biopsy, 67% returned for future screening. For women who received false-positive results on two consecutive mammograms and were recommended to return for short-interval follow-up, only 56% came back for their next screening mammogram.

They also found that Asian and Hispanic/Latinx women were the least likely to come back for screening mammograms after a false-positive result. They didn't evaluate the reasons for differences across racial or ethnic groups in this study, but Miglioretti has her hypotheses.

"It could be due to language barriers, different cultural beliefs and attitudes, challenges navigating the health system, financial concerns, or less trust in healthcare providers," she said. "It is important for future studies to investigate reasons so we can develop interventions to reduce health disparities."

For women ages 40 to 49, false-positive results occur in 10 to 12% of mammograms and after ten years of annual screenings, 50 to 60% of women will have at least one false-positive result and 7 to 12% will have a benign biopsy.

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