False-Positive Mammograms May Discourage Subsequent Screenings

Women who received false-positive mammography results were less likely to return for screening, especially if they received recommendations for short-interval follow-up or biopsy, according to a study of participants from the Breast Cancer Surveillance Consortium (BCSC).

In a cohort of more than 1 million women, 76.9% with a true-negative result returned for subsequent screening within 9 to 30 months, but this proportion decreased by:

• 1.9 percentage points (95% CI -3.1 to -0.7) following a false-positive recall for additional imaging only
• 10 percentage points (95% CI -14.2 to -5.9) following a recommendation for biopsy
• 15.9 percentage points (95% CI -19.7 to -12.0) following a recommendation for short-interval follow-up

Relative to those with two negative screening results, women who had false-positive recalls on their two most recent screening mammograms were 5.5% to 7.9% less likely to undergo a subsequent screening mammogram, reported Diana Miglioretti, PhD, of the University of California Davis, and colleagues in the Annals of Internal Medicine.

“This raises concerns about the potential unintended consequence of false-positive results on the continued participation of women in routine screening,” they wrote. “Physicians should educate their patients about the importance of continued screening after false-positive results, especially given the associated increased future risk for breast cancer.”

In an editorial accompanying the study, Neha Pathak, MBBS, MD, and Michelle Beth Nadler, MD, MSc, both of the Princess Margaret Cancer Centre and University of Toronto, noted that the U.S. Preventive Services Task Force recommendations on breast cancer screening were recently changed, reducing the recommended age to initiate screening to 40.

“Of note, there is a greater likelihood of false positives in women aged 40 to 49 years because breast density tends to be higher before menopause,” they wrote. “With the change in guidelines, it is expected that more women will initiate screening at age 40 years. Miglioretti and colleagues’ findings raise concern that the higher incidence of false positives from 40 to 49 years could discourage screening at older ages.”

As for why women discontinued screening, the study authors surmised that one explanation could be that the experience was so negative that it discouraged further screening.

“Offering same-day interpretation and diagnostic work-up of screening mammography may decrease the anxiety and inconvenience associated with having to return for a second visit,” they suggested.

The editorialists agreed that such an approach might reduce stress, but questioned whether it would actually reduce anxiety, and further noted that the resources necessary to undertake a diagnostic work-up aren’t available at all screening centers.

Solutions would likely be multifactorial, Pathak and Nadler added, with a focus on improving provider-patient discussions “both before initiating screening and during healthcare follow-ups.”

For this observational study, Miglioretti and team included 3,529,825 screening mammograms (3,184,482 true negatives and 345,343 false positives) performed from 2005 to 2017 among 1,053,672 women ages 40 to 73 years at 177 breast imaging facilities participating in the BCSC.

Mean age at mammography was 55.6 years, and 71% were white. Most (64%) screening mammograms were performed on women who had had a mammogram in the prior 18 months.

Overall, 9.8% of screening mammograms had a false-positive result, 5.8% had immediate additional imaging only, 2.7% were recommended for short-interval follow-up, and 1.3% were recommended for biopsy.

Asian and Hispanic women had the largest decreases in the probability of returning after a false positive with a recommendation for short-interval follow-up (-20 to -25 percentage points) or biopsy (-13 to -14 percentage points) compared with a true negative.

Miglioretti and colleagues acknowledged the study had limitations, including the fact that they did not capture the complete history of false-positive results over all prior screening mammograms.

“However, our results suggest the most recent screening result is the most important predictor of future behavior,” they wrote. “Women could have returned to screening at a facility outside the BCSC capture area, and it is possible that women with a false-positive mammography result are more likely to switch facilities if their false positive was associated with a negative experience.”