False-positive results raise suspicion for breast cancer and lead to further testing, such as additional imaging or biopsy, but do not result in a cancer diagnosis.
Recent evidence from the Breast Cancer Surveillance Consortium suggests that the 10-year cumulative risk of at least 1 false-positive result is 61.3% for women starting screening at ages 40 or 50 years and 49.7% for women aged 66 to 74 years undergoing annual screening.
Among 10 000 women aged 50 years undergoing annual mammography for 10 years, approximately 6130 ( 95% CI, 5800-6470 ) will have at least 1 false-positive result.
The risk of false-positive results increases when screening starts at younger ages or occurs annually, leading to more mammograms; this was a key consideration influencing the USPSTF recommendation to pursue biennial screening starting at age 50.
The significance of a false-positive result for an individual woman, however, is debated, and likely varies substantially by patient.
A review of 23 observational studies concluded that false-positive mammography results increase anxiety and distress related to mammography and breast cancer but do not increase clinically diagnosed anxiety and depression.
There are conflicting data regarding the persistence of anxiety or depressive symptoms over time, and whether women are more or less likely to return for subsequent mammograms after a false-positive finding.
About 7.0% to 9.8% of women experience unnecessary biopsies after 10 years of annual screening, approximately 940 ( 95% CI, 740-1150 ) of the 10 000 women aged 50 years undergoing annual mammography. ( Xagena )
Lydia E. Pace LE, Nancy L. Keating NL, JAMA 2014;311:1327-1335