Age and breast cancer risk factors associated with false-positive mammography results

1. From a retrospective analysis, rates of false-positive digital mammography results were highest in women aged 40-49, while no significant differences were identified between age groups for rates of false-negative mammography results.

2. Several breast cancer risk factors were associated with higher rates of both false-positive and false-negative mammography results across most age groups.

Evidence Rating Level: 2 (Good)

Study Rundown: The potential harms involved with mammography screening for breast cancer include false-positive and false-negative results, followed by additional screening and biopsies. The authors of this study, therefore, sought to estimate the rates of false-positive and false-negative results, as well as the rates of additional imaging and biopsies, from a retrospective analysis of women who underwent screening. From this, the rates of false-positive results and additional imaging were highest in women aged 40-49, which decreased with increasing age. Rates of false-negative results and biopsy recommendations, in comparison, did not differ greatly among age groups. Several breast cancer risk factors were also found associated with higher rates of false-positive and false-negative results, as well as additional imaging and biopsy. Specifically, a family history of breast cancer, high breast density, and previous benign breast biopsy result were statistically significant risk factors for false positive results across age groups. This study may be limited due to the design of the trial, which estimated these rates on a single round of screening. Therefore, the study does not reflect the potential longitudinal screening experiences of women most common in clinical practice. Overall, the study suggests that age and specific breast cancer risk factors are linked to higher rates of false-positive mammography results and additional imaging.

Click to read the study published today in the Annals of Internal Medicine

Relevant Reading: Consequences of False-Positive Screening Mammograms

In-Depth [retrospective cohort]: In this retrospective analysis, data was collected from the Breast Cancer Surveillance Consortium (BCSC) between 2003 and 2011. Specifically, 405,191 women aged 40 to 89 years that had routine screening were included in the study. If women had completed more than 1 mammography screening during the study period, 1 observation was randomly selected to be included in the calculations in order to reduce potential bias. In the analysis, false-positive results were common in all age groups, but highest among women aged 40-49 years (121.2 per 1000 women [95% CI, 105.6-138.7, p < 0.001]). This rate decreased with increasing age, where only 65.2 per 1000 women aged 80-89 had a false-positive mammography result (95% CI, 58.8-72.2, p < 0.001). False-negative results ranged from 1.0 to 1.5 per 1000 women, but there were no statistically significant differences between age groups. Furthermore, rates of false-positive and false-negative results did not differ in comparisons of time since the last mammography screening.

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