A new large, multi-center cohort study published in the Annals of Internal Medicine reveals an unintended consequence of the breast screening process: women who receive false-positive results are less likely to return for subsequent screenings. This finding raises significant concerns about the long-term effectiveness of breast cancer screening programs and highlights the need for strategies to mitigate the negative impact of false positives.
The study conducted by researchers from the University of California, Davis, analyzed data from over three million screening mammograms performed between 2005 and 2017. The study cohort included more than one million women aged 40–73 years from 177 breast imaging facilities participating in six U.S.-based Breast Cancer Surveillance Consortium registries. The researchers aimed to evaluate the association between the results of screening mammograms and the likelihood of women returning for subsequent screenings.
The study categorized women based on their mammogram results: those with a true-negative result, where no breast cancer was detected, and those with a false-positive recall. A false-positive recall occurs when a mammogram suggests the presence of cancer, leading to additional imaging, follow-up, or even biopsy, but ultimately no cancer is found. The researchers then assessed the absolute differences in the probability of returning for screening within 9–30 months based on these results.
Among women with a true-negative result, 77% returned for subsequent screenings. However, this percentage decreased significantly among those who experienced a false-positive recall. Specifically, the likelihood of returning for a subsequent screening decreased by two percentage points for women who were recalled for additional imaging, 16 percentage points for those who were recommended for short-interval follow-up, and 10 percentage points for those who underwent a biopsy that ultimately revealed no cancer.
Notably, the impact of false-positive results varied across different racial and ethnic groups. Asian and Hispanic/Latinx women were the least likely to return for future screening mammograms after experiencing a false positive. These findings raise concerns about potential health disparities and suggest that certain populations may be more vulnerable to the negative effects of false-positive results.
“While we did not evaluate reasons for differences across racial or ethnic groups I wonder if 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,” says first author Diana Miglioretti, PhD.
The psychological toll of false positives
The study’s lead researcher highlighted the surprising nature of these findings, noting that survey studies often suggest that women believe they would continue with routine screenings even after a false-positive result. “I was surprised by the findings, as survey studies suggest that women believe they would be just as likely to continue screening even after a false-positive result,” Miglioretti explains. “However, something about the experience seems to influence their actual behavior, and despite their intentions to return, some do not.”
This discrepancy between intention and behavior may be rooted in the psychological toll of false positives. Women who receive a false-positive result may experience anxiety, fear, and mistrust in the screening process. This emotional response can deter them from returning for future screenings, even if they understand the importance of early cancer detection.
The study also found that a false-positive recommendation for short-interval follow-up had the greatest impact on a woman’s likelihood of not returning for future screenings. “I was also surprised to find that a false-positive recommendation for short-interval follow-up [meaning, the woman had to return in 6 months for diagnostic imaging to evaluate changes in the abnormal finding] had the greatest impact on a woman’s likelihood of not returning for future screening,” Miglioretti says. She initially expected that the probability of returning would be lowest for those who had undergone a benign biopsy. However, even after following women for five years after a false-positive result, women who received a short-interval follow-up recommendation—meaning a return for diagnostic imaging in six months to evaluate any changes in the finding identified on screening mammography—were the least likely to return for future screening mammograms.
Implications for breast cancer screening guidelines
The research team believes their study has important implications for current breast cancer screening guidelines. The 2024 U.S. Preventive Services Task Force recommends starting breast cancer screening at age 40, with screening intervals of one to two years. However, the study suggests that false positives, particularly among younger women, may undermine the effectiveness of these guidelines.
“Our study highlights an unintended consequence of false positives,” says Miglioretti. Notably, women in their 40s are at the highest risk for a false-positive mammogram, with 10–12% of screenings yielding a false-positive result. Over ten years of annual screenings, 50–60% of women can expect to experience at least one false positive, and 7–12% may undergo a benign biopsy. Given the significant impact of false positives on future screening behavior, Miglioretti and colleagues believe it is crucial to address this issue to ensure that women continue to participate in routine screenings.
One potential solution is to enhance communication between healthcare providers and patients. Says Miglioretti, “To reduce the anxiety associated with false-positive mammograms, it is important for clinicians to explain that diagnostic work-up of screening mammography findings is an important and common part of the screening process and that they almost always turn out to be normal—even the majority of short-internal follow-up and breast biopsies are benign.”
Still, Miglioretti points out that after a finding is found to be normal, it is important for the clinician to explain that cancer has been ruled out; however, “individuals need to return for routine screening because they are still at risk for breast cancer in the future. In fact, having a false-positive result slightly increases the risk for the development of breast cancer in the future, and cancer risk increases with age; therefore, women should continue screening through age 74.”
